So I've been thinking a bit more on diplomacy and how it could be made more interesting, and I figured that this might be the thread to add my thoughts on this issue.
As I understand it, the next expansion is meant to upgrade this aspect of the game which is good, and I don't really know what the devs have planned, so who knows if any of this is already on the docket or not, but I figured I'd go ahead and pitch these ideas out anyway.
So first, I want to describe the scenario that led to my first win as the Terran Alliance, and something I've partly used again as Iridium Corp (though I turned off the diplomacy victory in that case, so I could just ensure peace while I pursued culture/tech victory).
And I'm going to state outright that I'm pretty new to the game, so there's undoubtedly a pretty high chance that I'm covering ground that's been discussed before on these forums. So for any old hats out there bored with these thoughts, I apologize. Hopefully there's something in here that's interesting at least.
The Optimal Diplomacy Game
So, with the introduction of diplomat citizens, the general conflict with upgrades to flat diplomacy buffs that likable races get and the tech tree can unlock is that a player can basically combine everything to resolve any real tension one has with another civ really fast. It's how I won my first game at least (large size map, playing as Terran Alliance on normal).
Here's what I did - primarily focus on the diplomacy line to the somewhat exclusion of all other techs (mostly spreading into the basic development of the starts of each major branch and some extra hyperdrive speed boosts to hurry communications along in addition to this line). Make sure to pick diplomatic reasoning as your first specialization too. This gives +1, +0.3, +0.5, and another +1 just through tech bonuses. If you have the likeable stat like the Terrans you also get another +1. Already, you're looking at a rounded up +3 or +4 to all civs, which erases any potential difference in ideology you might have with any civ.
Now, over the course of this period of time, you can go at least 50-60 turns and generate 5-6 citizens. Presuming the first one or two occur before you unlock the ability to train diplomats, you can get 4 diplomats by turn 50 or 60.
Build at least one trade ship for each civ and send them to all of the capitals of all civs, and build enough ships so you're not an easy peasy war target right away. The map size changes the amount of time this takes of course, but on most except for the largest, it's achievable within those 50-60 turns. Don't expand your borders too much, and make sure you pick enough malevolent ideology points when colonizing to pick the first Awe line bonus to erase any negative penalty you can get from shared borders. The rest should go Pragmatic so you first unlock the first two negotiator perks ASAP. The first one will prevent any wars with you whatsoever in this 50-60 turn window of time (but you should wait just a bit before you grab it, probably picking up the Awe perk and the constructor perk first for advantages) and then the one after that, will grant another flat +1 to diplomatic relations.
If you get enough colonies, put the ideology points into the traders line to try and get that extra buff to diplomacy for trade routes, and work on that tech line when you get the chance, but prioritize the diplo line (which is fairly short) most of all.
By turn 60 you should be at no wars with anyone, have 4 deployable diplomats, and have at least a +4.8 base modifier with all civs and the ability to lower tensions through open borders treaties and something everyone wants, like an economic treaty, as well as hopefully establishing at least one trade route with all civs.
Combined, you should at least be not at war with anyone before the war immunity wears off and you start deploying those diplomats. Which you will then do systematically, assigning all four of them to each civ that you're not already at alliance capable relations with (those you just ally with immediately). Each turn you assign all four of them to a civ, get to the next turn, and you should be able to ally with them in most cases. Certainly, since you're going pragmatic, this should work for all the pragmatic civs in the game.
After you create a pragmatic power bloc alliance system, move on to the remaining benevolent civs with the diplomat barrages. In general, though the altarians might give you some trouble, you should be able to integrate them into the fold too.
So long as you do this quickly, within the first 100 turns or so, you can usually create a benevolent/pragmatic super bloc alliance that bolsters itself diplomatically into unbreakable bonds pretty quickly, since everyone is getting strong "you're allied with another ally" bonuses. At the very least, no one will want to break alliance with you since you've got trade routes, alliance network bonuses, diplomats, and high base diplomacy modifiers.
The tricky ones will be malevolent civs of course. But some are surprisingly amenable, like the Yor, so long as you build up enough forces to not present an immediately tempting target. I also notice that the Yor seem to like to over expand rapidly, and tend to have crap economies for a while as a result, so they really appreciate the trade routes and economic treaties a lot. The Snathi and the Drengin of course, really won't like you much, but you might still be able to include them in your alliance network, or at least one of them, if you get one of them within your invulnerability to war declarations window.
From there you're looking at, probably at worst, having to start a big power bloc war to wipe out the remaining holdouts. Since you're so buddy buddy with EVERYONE else, these wars should be over pretty quickly, as you'll arrange for several civs to attack a malevolent isolated civ all at once, and lead the charge yourself. Even then, it's even smarter if you can just convince all the other civs to attack the holdouts while you don't, because you still might be able to diplomat barrage them into an alliance in certain scenarios/timings. Or you can get them to just surrender their planets to you once the joint coalitions you're manipulating against them quickly pick them apart.
By turn 200 hundred, you should win. Faster if you personally take the time to wipe out a weaker malevolent civ or two yourself. You'll have a few grumbles here or there from your allies, but those high "ally with my ally" and "enemy of my enemy" bonuses combined with the strong base diplomacy buffs should keep people from ever wanting to break with you.
So what's the problem with this scenario? It is, essentially, optimal play. And it presumes little can go wrong. It's also assuming normal or gifted difficulty only (as those are what I've played on so far, but I think those are reasonable picks to presume for newer players like myself).
The main issue is that there's a redundancy between the way the Diplomacy techs used to work pre-Crusade, and the addition of the diplomat citizens now that they exist. Essentially, you can, with full diplomacy techs, and four diplomats, keep any civ you want neutral to you at any time you want, especially if you take war off the table with that first Negotiator perk. Because you're looking at something like a +7.8 to a +8.8 modifier in a turn without factoring any trade routes, any declarations of friendship, or any treaties that ease tensions like open borders.
That is an IMMENSE modifier that is completely actionable by the player at will and super fast, since it only takes a single turn to give a massive diplo bonus to any particular civ you toss four diplomats on.
In fact, if you stay relatively neutral with everyone for a while thanks to that window, and go all in making diplomats so you have 8 or 10 of them, you can do stuff like put all of them in the malevolent civs on one turn, then on the next craft alliances with most everyone else AND the malevolent civs all in one turn, and just forge a massive multi-civ power bloc in that turn, because a lot of diplomatic shifts don't really occur until you hit the next turn button (since this seems to "initiate" the treaties).
You can effectively rope AIs into alliances with civs that might be enemies with each other this way. It tends to ease their tensions on the next turn a lot since they're now getting "ally with my ally" bonuses that ameliorates several prior maluses, and so long as they were just having tensions and not already involved in long wars, you can often get them to at least neutral states this way within a single turn or two.
At the very least, I find it really easy to make sure I prevent any and all wars against my civ this way. Except for those I choose, and those that might occur very early before I trigger that immunity in the pragmatic line. And this is a huge advantage, since I means I can do stuff like build up my fleets or develop my worlds in a really safe manner from there on in.
So, some proposals:
1) Change the Diplomacy bonuses from flat increases on relations to increases in the number of diplomats one can deploy to civs, at least for Crusade.
Basically, rather than getting a flat +1 or +0.3 to relations along the tech tree upgrades, the main upgrades in diplomatic tech unlock the available slots you can assign for diplomats. So, that, when you unlock the Diplomacy, Interstellar Alliances, and Eminence techs, each grants another available slot in which you can assign a diplomat to any given civ. The Terran trait of Dilomatic, building the Diplomatic Corps achievement, and the Diplomatic Specialization also grant another slot too, but the max should still probably be only 4 or maybe go up a notch to 5.
This would remove a flat 2.8 from your relations with everyone, and it would mean that you have to actually assign diplomats to civs in order to try and gain that ground back. It would also mean that unless you put the effort into the techs AND in training the diplomats, you're going to have to deal with negative modifiers longer, building up longer periods of relationships that could lead to earlier conflicts that diversify the diplomatic landscape into fractures that are harder to mend easily or early.
2) Make assigning a diplomat to a civ, or removing one incur travel time.
Pretty simple, but when you choose to assign a diplomat to another civ, it basically creates a "mission" civilian craft that has to fly over to the capital planet of the civ in question before that bonus gets applied, rather than simply applying next turn.
This would change diplomatic geography a bit. Making it harder to quickly change relations with civs who are further away, and a bit easier to change relations with civs that you're bordering. But that allows for interesting developments to occur in the meantime that can cause different things to occur.
It also means diplomatic citizens might be vulnerable, if civilian "mission" ships are targetable (I actually haven't tried this yet). In which case, having one faction kill another faction's diplomatic envoy could create a negative modifier with other civs. Stuff like "they killed an ally's diplomat" for allies of yours, or for benevolent factions "they broke the rules of peaceable conduct" more generally.
2.5) Make all diplomats assigned to planets for influence growth buffs have the "Go to General Pool" promotion.
This is just a Quality of Life improvement really. Since diplomats, like spies, are unique compared to other citizens in that they have an alternate function aside from the more binary choice of "in the government bureaucracy or assigned to planet" bonuses, they should get the same promotion engineers and workers currently have so they can be more flexible.
In general, I'd prefer if all citizens had this, personally.
3) Have Diplomats "Working for the Government" raise base diplomatic rating by 0.2 each instead of getting basic bonuses through tech upgrades. Or have slots on your own civ in the diplomacy screen for this specialized function.
Basically, since we're removing a lot of the sources of the "your skill in diplomacy" bonus through basic flat bonuses you earn through tech upgrades, it gets reassigned here. Either to leaders and diplomats assigned to the "Influence" office in your government, or possibly in creating a new government office that specializes just in diplomacy other than the Influence assignment.
Diplomats could raise this by 0.2 each. Leaders by 0.3 each. Since there are 10 slots, this could at max, grant you a +2 with 10 leaders or a +2 or a +3 if completely filled up with leaders.
The alternative to this would be to have a number of slots available for your own civ on the diplomacy screen viewable. That you can assign them here on this screen and that's where they raise your general diplomatic bonus and its flat rating, but this leaves them still available to be assigned in the Govern menu to raising influence as a separate function.
This would again, slow down general diplomacy gains a bit, leading to greater tensions longer. It would also mean you can still achieve that huge diplomatic buff where everyone pretty much likes you and won't war with you, but it will take concentrated effort and sacrificing a lot of other bonuses to achieve. It should make this a much more "interesting choice," which is usually the 4X ideal, I think.
4) "Diplomatic Incident" Events that trigger when your diplomats arrive on a civ's planet, or whenever two allied civs to yourself incur a penalty with each other greater than a 1-point shift.
Similar to how you trigger ideology choices whenever you colonize a planet, there could be a trigger condition to create a new chance at ideology points when you send diplomats to a planet. To balance things out, it should probably not be a 100% chance to occur at the start, but each additional assigned diplomat raises the chances of this occurring. So if there are four diplomat slots, the first has a 25% of occuring, the second 50%, the third 75% and the fourth 100%.
These events could cause a chance to gain a small amount of ideology points (since they're repeatable, it shouldn't be in massive amounts, like 5 or 10 at most) but more importantly, they can potentially grant additional maluses or bonuses to your diplomatic relations with that civ for a set number of turns or permanently, depending on the event, as well as other potential effects (like a free instant trade route between that planet and another, or a cost in cash et cetera).
In addition to that, you can also get "Neutral Party" events that occur between a pair of allies that you have whenever events occur that shift their relations. These would be about forcing the player to choose whether or not you favor your alliance with one civ or the other as tensions between them rise, or choosing to try and split the difference for some kind of cost (in large amounts of gold or in a key rare resource you might have access to) in order to try and maintain your relationship with both parties.
That would mostly be there so that alliances remain more interesting over time, rather than slowly turning into static power blocs thanks to the large "ally of my ally" bonus. Enough that potentially, you'll see shifts in alliance blocs over time.
5) Other civs' diplomats take up diplomatic slot space.
This is one I'm not even sure about, but it might be interesting to consider as well. But basically, the available diplomatic slots a civ has on the diplomacy screen can be taken up by other civs' diplomats.
This would allow you to see how the AI (or other players, potentially) are playing the diplomacy game themselves. So you could see that the Terrans have sent a diplomat or two to the Altarians, preventing you from sending any yourself until they reassign them to some other faction.
This could then create an interesting diplomatic game where one can block the the ability of a certain civ to raise their relations with other civs. It could also be interesting to see who sends diplomats to YOU, if the situation is that there are open "embassy" slots on the diplomacy screen for your civ. Having another civ send their diplomat to you would give them a bonus on relations with you "They have sent a diplomat to your embassy," but it would also potentially prevent you from raising your general diplomatic rating with all civs at once.
Again, a game of using diplomats as weapons, of a sort. Pawns that open or block available movement for diplomatic improvement. So you could get machiavellian with the system and engineer poor relations between two civs but not your own with some effort and smart plays.
6) Equalization and Permanent Bonuses and/or Maluses.
Basically right now, diplomacy is a series of binary bonuses or maluses that add up to get to a total score. You get a + or a - for each little difference in diplomacy between you and another civ.
This is fine, and works well for the most part. But with certain elements it might be interesting to add a third state, equalization, represented by the = sign.
Basically, with diplomats, you can send one to them to get a + of "Your diplomats vouch for you." But if you send one to them, and they send one to you, then perhaps those diplomats cancel each other out at that point to just become "Your respective diplomats bicker for advantage."
Another element here would be to better represent with more granularity the aspect of declaring friendship. Where your declaration for friendship with them versus declarations of friendship with enemies drops into an equalization state first before you get that negative mark of "you've declared friendship with their enemy" to "they question your statements of friendship" first.
On top of this, certain actions or states could be made permanent bonuses or maluses over time or depending on their severity.
Certainly, if you take a civilizations home planet, you should probably get a permanent malus with them based on that at least. And if you've been in alliance for an exceptionally long time (perhaps it's a ratio so that it's an equal number of turns to the amount of turns before you were allied plus a modifier) you can get a permanent "You've been long term allies" bonus.
(I know they're already adding a long term allies bonus going forward, but this could be an even stronger version of that if enough turns pass with that active perhaps).
7) More complex effects for trade relations.
So, the way trade routes with other civs work is that one civ definitely has an advantage over the other depending on who starts the route. Both receive benefit, but there's definitely an advantage to one civ or another depending on who starts them. As there is this imbalance, it could be interesting if this were reflected in the diplomatic screen too.
So basically, aside from the first trade route either civ sends each other (which should basically be "free" in terms of how they affect diplomacy) trade route advantages could create trade deficits based on how much value they generate. So if you send the Arceans four trade routes and they only send two to you, and this results in the b.c. per turn they generate for you to generate more than double the b.c. per turn it generates for them, you get a first level diplomatic malus of "they have a trade deficit with you." On the opposite end, if they send more trade routes to you than you to them, you'd get a diplomatic bonus with them of "you have a trade deficit with them."
Basically, they like it when they're making more money off of you than you are off of them, and vice versa.
If this was implemented you'd have to change how the diplomacy buffs for trade routes work in the Pragmatic ideology bonus and the bartering tech of course. But the general idea would be that the more bartering tech you have versus their own, the less these potential negative effects can occur, so you can have more trade routes with a civ that favor yourself than with them.
These are just some other diplomacy related ideas I've had that don't fit into the above stuff concerning how diplomats and core diplomacy bonuses and maluses work.
8) Citizen Hostages can be trade-able/ransomed.
So, sometimes when you take a planet you get access to the citizens the prior civ has already assigned to that planet. If at the end of the war neither side is destroyed, it might be more interesting to make these citizens hostages rather than just letting the civ that captured them use them right away.
Perhaps when a planet with citizens on it is captured, these Citizens go into a unique state - Imprisoned. If you raise your cultural influence, this state can become "Re-educating" and over time, you can then use them for your empire. But when in either state, if the civilization you gained them from hasn't been wiped out, you might be able to bargain for them.
Heck, they might make very good bargaining chips for why a civilization would want to sue for peace, or conversely, why you might want to. At the very least, at the end of a war, you should be able to ransom them back to the civ to put them back in their general pool of citizens for cold, hard cash.
Potentially, it would be very interesting if combined with:
9) Advanced trade missions require available entrepreneurs, research missions require scientists.
Basically, right now you can pretty easily spam the various trade missions when at peace and you're not building up your fleets. As something basic to do, this is a neat feature and I like it. But often, the bonuses gained from these actions become really weak as the game goes on.
It would be neat if there were higher tier civilian missions for several trade missions that required an available citizen to access. Basically, that the lower tier missions might just send drones or random groups of civvies off to explore space or a dead planet somewhere, but better versions would actually have citizens on those ships that fly out. This could expose them to capture of course, but the potential rewards could be a lot higher.
So the general trade mission wouldn't generate its standard alotment, of a couple hundred b.c. as it is now, but maybe the advanced one grants around 1000, plus or minus 200. The scientific mission grants 50 science right now, but it can get 200 with a scientist on board. An engineer can go on advanced salvage missions to bring back medium ships, but the normal salvage teams can only bring in tiny or small ships. And farmers can go off and find you a little monsantium. After the mission completes, the citizen returns to your pool, but you can make this choice to lose their normal abilities for a few turn for the eventual burst effect.
10) An equivalent to "nukes" reflected in diplomacy - Doomsday weapons (aside from Spore ships).
Essentially, as most people know in the modern day, a lot of diplomatic relations revolve around nuclear weapons, Mutually Assured Destruction relationships, and the sale or trade of nuclear technology.
In the Civilization series, this is reflected in diplomacy with just that exact technology. Nuclear weapons create a lot of fear amongst other civs the first time one is used to destroy a city (or even just built). Soon you can get cold war-esque nuke races, and it's a big part of the late game.
To get to an equivalent in GalCiv, or any space based 4X, you'd have also include potentially equally devastating weapons of mass destruction, but of course, scaled up immensely.
But of course, thanks to Star Wars, this concept's been around for a while in the form of the Death Star, and GalCiv already has the concept of Spore ships, for example. But it would be very interesting if various kinds of "Death Stars" were buildable at the higher end of the tech tree (and which would sort of be alternatives to starbases, in that they use administrators on top of other normal, very high costs).
In terms of diplomacy, these kinds of weapons of extreme destruction could be the equivalent of nuclear armaments, both increasing the perceived threat of your civ immensely, and forcing other civs to either try and compete themselves, or try and commit a joint action to destroy your highly threatening weapon of galactic destruction. Spore ships, potentially could be classified in this category too, so if you make them through admiral promotions you'd also raise the diplomatic stakes immensely.
Realistically, in terms of diplomacy, this already falls somewhat in the area of "they are worried about your military buildup." But it would have to have it's own category unique to itself to really create the proper effect, and one of very high threat and major diplomacy penalties. Unless of course, you were dealing with an ally who also has a similar weapon. In that case, they might equalize with you on this issue to some degree, though it still should probably be a major point of tension.