I posted my initial thoughts in another post. After blitzing through many games the last few days, I have organized a much deeper look at the game. I have long been in the GC family, and hope that this feedback will be an aid to you in making it the best game it can be.

UPDATE: I wrote this article after I had played a "large number" of games. Now that I have played a "whole whole bunch" of games, my feedback on a few things has changed. I am noting a (**) for items that I have updated feedback, with the updated notes below the original (aka the original notes are not changed).

Overall Summary

• Most of the brand new GCIV mechanics I like, they are solid improvements to the game. I think the potential for them is there, and I think the economic "core" is a lot more solid than when GCIII first came out. In summary, the foundation is solid.
• The game feels unpolished and empty...which is pretty typical of every 4x game I play at version 1.0 nowadays. That said, there are a lot of bugs, many of which are quite ugly and noticeable, that do detract from the experience.
• My biggest concern is the game generates the same feeling I had in GCIII (which I ultimately lost interest in). The beginning is very fun, and then the middle becomes hollow, empty, and most of all... tedious. There are lots of techs and lots of ships and lots different resources and lots of XYZ....but I still don't know why I'm doing anything. Note that while most 4x games have this problem towards the end of the game....I feel it a lot sooner in GCIV. This is where I think your galactic events have a lot of potential to solve that, though they aren't there yet.
• When I think of your UI, the word tedious comes up a frustrating amount of times. So many things to me require too many clicks. Also I find information is not organized like I would expect. To get to X I right click on the ship, to get to Y I double click, etc. 

Asteroid Mining

• Mechanically, this is in a good place. I don't mind losing my mining ship to make the base when I can snap 3,4, or even 5 asteroids at a time. The bonus is solid and meaty, and I actually get excited when I see clusters of asteroids.
• UI, the biggest issue here is two fold. First, I don't think mines should ever go to a colony, they should always go to the nearest core world (especially since distance does not seem to be a factor. If that is not intended (a bug), then I personally would consider removing distance entirely. Its a chance to create the "tall planet" that others have noted as a concern for the game). Second, changing asteroid ownership is very tedious.

Colonies

• The colony concept is solid. You have a bunch of dinky planets that help the big daddy, works great, reduces my micromanagement bloat in a way that makes sense. I'm on board.
• My biggest issue with colonies is....apparantely I still have pollution/crime/approval....but I am not sure why I should care. Is the 50% approval dropping my base 3 manu to a 1.5? Is there actually anywhere to see crime for a colony? There is no insight into how colonies work (are they improved at all...do they grow pop over time?), but I am still expected to make some decisions for them like they were a core world.
• Because of point 2, I find most of the colony upgrades very mediocre. There are literally only three types of colony upgrades that are worth considering to me:
• +X (not %) to manu/research/wealth/farming: A solid and meaty bonus, worth my time.
• Gives me X of a strategic resource per turn
• Defense: If my colony is in hostile territory, this miiiiiight be useful...though I doubt it.

Culture / Ideologies

• The Ideology system is leaps and bounds better than the older versions. Its more interesting, dynamic, and just thematically makes more sense.
• **The system currently suffers from a criminal lack of culture. I don't like how difficult it is to get culture, my first culture point is often granted way too late in the game, and it seems I mostly have to push it myself through mini wonders or wait until the event gods grant me some. I want a more concrete way to generate culture.
  • UPDATE: With experience, I have learned how to manage culture better and "find the points" in the system. I still think culture points are sparse in the late game, but I know longer find early culture a problem.
• There are some major imbalances in current tenents. A quick example, the +3 constructor one could be great if it was a tier 1 tenant available within 10 turns of the start. But when its 40 something turns before I get a culture, I will never spend it on a one and done bonus.

 Diplomacy

• This is an area I think Gal Civ is falling behind other modern RTS. I don't feel that diplomacy has evolved in any real way.
• Currently, the AI is incredibly stingy. I cannot get fair deals to save my life, the AI wants to gouge me every opportunity it can get. As such, I never want to make deals.
• The new diplomatic credit does nothing for me. We already have this.... its called a credit. I won't accept DCs because I don't have immediate use for them (and the AI will just gouge me anyway). Also UI wise, while credits very nicely pop up the exact amount you need to equalize a deal, DCs I have to count out manually.
• Another pet peeve of mine if there is no summary screen to show me what resources the other civs have access to. I have to click on them one after the other after the other to determine who has the resource I want.

Executive Orders

• Effectively an expansion on your artifact concept, the general model I think is solid.
• Currently this mechanic suffers from long cooldowns. The amount of control I gather is never my problem, I burn through my orders...and then I'm waiting forever for the cooldowns to finish up. I never care about getting more control.
• This is an area where the mechanic becomes much better with more content. The model is nice but you very quickly are just using the same orders again and again and again.
• I would like an "archive" of certain orders. Example: The colony ship is a great order early in the game, and almost never used in the late game. I don't want to keep seeing it in my main screen, would be nice to put those in an "archive" and require me to click a few more times if I actually want to use that one.

Galactic Events

• One of your new selling points, and I really like the concept. I have been playing Old World recently, which was a good implementation of this, but sometimes I always went "darn, why couldn't I have gotten that quest 15 turns sooner/later". I think you have nailed that with this system, a way to beat the game on my terms in my desired way.
• One change I would like is for the summary bar at the bottom of the screen to note numbers when a new galactic challenge is viable to take. I often forget way too often about them, and suddenly realize there are a lot of them available.

Leaders and Citizens

• **The new leaders are working well. Ministers are solid, governors are useful, commanders are my favorite iteration of that concept yet. The one area that's lacking are the factions. Some civs like the Corporate Sector have a few really good factions, but in general I find the factions pretty ho hum, and often not worth buying more leaders. I think leaders just need more special modifiers to make them more engaging, but the core model is solid.
  • UPDATE: With more experience, faction bonuses aren't as bad as I first thought. However, the UI is really a detraction here, its just really hard to remember which factions use which stats. I wish that was prominently displayed for each faction rather than just having it in the toolbar. 
• The stats on citizens I find more tedious than anything. I really don't need individual stats (especially on approval). I would just rather Iridiums be generically good at X role, Altarians at Y, etc.
• I would like some setting on a planet that automatically changes any new citizen into X role. Having to go back to the planet time and time again to check for new citizens is tedious.

Manufacturing/Research and Approval

• Unless your approval is at 100%, approval boosters are strictly superior to research and manufacturing boosts. A 3% approval boost is normally equal or even superior to a +3% manu boost, AND since it also applies to research as well you get double your value. Approval buildings don't generate pollution (only crime, which doesn't hurt much if your focus is on manu/research over wealth, and even then approval buildings give adjacency to wealth so you can slip in a wealth building to compensate for the crime). Unless I get a massive synergy bonus to a manu or research building I always go Approval now until I hit 100%.
• **One issue is that planets with 1 manu (even high quality planets) are very hard to work on. They build very very slowly, and so either you have to dump a crazy amount of credits to get their basic structure up, or you just let them hang out without much infrastructure. While there are some policies and things that can help (like asteroids), its not enough compared to the value.
  • UPDATE: I think the reality here is, you should not be making 1 manu planets core worlds. They should instead remain a colony and feed another world until they can recieve regular supply shipments. So this is no longer an "issue" to me.

Planet Buildings and Adjacency

• The way the economic model works right now, almost everything is a % of the original planet's core yield. So what I find happens is, my planet's core yields (plus its colonies) drives everything....and the terrain itself almost means nothing. If my planet has a 5 manu and a 3 research, it doesn't matter that the planet has a lot of blue terrain with extra research bonus... the manu multipliers are so much stronger because they are based on a 5 rather than a 3, that I would much rather carpet the planet in manu buildings then diversify. Often your homeworld is strong enough in all of the core yields that I will diversify sometimes, but beyond that you focus on one yield and stick with it. This is a shame because it removes the interesting nature of the terrain and adjacency mini-game.
• I wish the building levels mattered more. Research buildings are +2% per level which is decent, but the manu's +1% is just not very exciting. I also wished some of the super buildings gave more core yields instead of percentages, that would make them more exciting.

Policies

• Another solid addition to the game. Polices are simple to use, and meaty enough to care. Some parts of the game they are fire and forget when I want them to be, but then I will switch it up for a particular combo when I need to do something.
• Some kind of "cooldown" is probably a good idea once policies are selected. I do think HP boosters are too gamey right now. I can switch to hp boosters right before a series of fights, and then switch back when the fights are over.
• Some people have complained that "tall" style is not encouraged enough in GCIV (or GC in general). I think policies are a good area to push this. You already have a few policies that work only on the homeworld or on core planets, add and buffing some of them is an easy way to allow more tall gameplay without major alterations to other mechanics.

Research Tree

• **I am on the fence with the new research tree. I get the appeal to force people to diversity instead of just beeling up the tree for the key thing they want. On the other, there are SO MANY TECHS in this game, at least in the old game I could go to the tech I wanted, click on it, and then the system would just tech, tech, tech through everything without me caring, until the tech I wanted was finished. Now I have to work the screen again and again and again. Honestly about half way in the game, I stop caring. I literally just click the first tech that's there, it all just blurs together.
  • UPDATE: The more I play, the less I like the new tree. I don't feel the 10% research penalty for switching, I just switch if I need to, and then I feel annoyed if I have to switch twice. But otherwise all the tree does is slow me down and make me forget to grab techs I wanted to take, because they weren't on the screen. The reason this concept works in other games (like Old World) is because you are forced to take what you are offered most of the time, getting to reshuffle is a big deal. And so for better or worse you are forced to play the hand you are dealt. Whereas in GC, this concept just doesn't serve any purpose to me
• So I'll say it again, there are so many techs in this game. The early techs are fun and interesting, the later techs are just "more stuff". I get 4 trade licenses, then 8, then 12....its just more of the same. I honestly wish the last third of the tech tree was condensed (heck maybe the last half). I want a lot fewer but meatier techs that take longer to research, techs that actually excite.
• One thing I would also like to see for later techs. You give a lot of free stuff with early techs, it would be nice to see some of that in the later game, give me a way to compensate for high research/low military. Maybe instead of 16 trade licenses, I insta get 12 freighters or something. That is a way to diversify later techs with an immediate benefit that sometimes is very appealing for me. Or maybe a tech that gives me 10 techapod hives.
• One UI thing that drives me crazy is how the techs in a certain tree can sometimes be a different color. This tech is on the colonization tree but its blue....so do I focus on colonization to get it or research? I still don't exactly know the answer to that question after several games.

Rush Buying

• One note here. I don't mind that I can only rush out 1 thing per season, but please let me queue up a bunch of rushes and then have them all come out 1 season at a time. It is so tedious to have to come back to the planet every season just to rush out my next ship (I would play the corporate sector more if not for this).

Ship Design

• Having now played through several games, the new "slot" design really feels like an improvement. I have fewer designs, but each design has a notable role, not just a tweak compared to the last, which I like a lot. This also means the newer fewer miniaturization techs are also very meaty and strong, feels great.
• Tiny and small ships hold their value longer as compared to previous Gal Civ games. I actually noted at one point that a fleet of tiny ships would beat out a fleet of small ones, but I could generate the small fleet faster. So it became a decision for a slower but stronger fleet, or one I could field quickly....a solid choice. Medium and heavier ships are now not just about "more power" but often more as an escort with fleet bonuses for a swarm of smaller ships, which to me is a far more interesting composition than just "all ships of the biggest size I can field"
• I dislike the various "+25% missile attack" modules. There is no strategy there, you add the module when it gives you more offense, and you don't when another weapon would give you more. Its not a tech I have to research, I have them for the entirety of the game (even early in the game when they are never worth it). Even the strategic resource is not a factor, as I can just do that on the weapons should I wish to. It takes up a lot of space in the designer, and for little purpose.
• The HP boost module needs a look at. +4 hp that takes up a full slot just doesn't compare to more offense or defense modules. The +50% hp in home territory is an awesome touch, and the durantium one with +20% extra is pretty good, but the base one needs a little love.
• I am not sure what purpose the Cargo hull serves once you get Small hulls. Small hulls hold more slots, are cheaper, and faster.
• One idea you might consider is to allow a few "slotless" items, but perhaps at a very high construction cost. This is an area where your hp modules and +25% attack boosters could find a niche, they are always addable because of their slotless nature, but their cost means you would only consider them for specialty ships.

Starbases

• The new module system is a great evolution of your GC3 "connected stardock" concept. Makes it easier but still keeps the connection between using the star dock to get more starbase power without endless constructors.
• **I am very happy that range boosting abilities are earlier in the game now, and the fact that mining bases don't seem to get it (a nice way to distinguish them). I do think military bases are too weak right now, but considering your plans to let them autoattack (which I love btw) I think that will shore them up. Influence bases have always been the red-headed step child, unless I am pushing an influence victory I just can't find the use for them compared to other bases. I wish they had a bigger range to start with, that would give them an interesting niche.
  • UPDATE: whereas I want thought not having range boosters on the mining bases was a nice differentiation...now I just got annoyed by the fact I can't have them:) Also I have softened on influence starbases, I have found that combined wtih the influence from sensors and defenses, a culture starbase by itself can make a very sizable difference in the border areas of a territory, and I have incorporated them more in my play.
• One serious pet peeve is that the starbases get the little symbol over their head when modules are available....but it doesn't matter which modules. Often I don't need defense or sensor modules, I am just waiting for more "core" modules to come online. I wish there was a way to remove classes of modules from detection, as effectively I have to go starbase by starbase right now to determine which bases don't have the latest core module.

Techapod Hives**

• This is the one resource I consider "overpowered" in the game.
• First, the fact that my mining colony's second module requires this is very frustrating in games where you don't have this resource, which is most of the time.
• Second, if you do have it, all of your key mining starbases get a major leg up on the competition in terms of resources.
• While there are other resources that I love having, none of them feel as impactful as techapods do, especially for a resource that there is no way to acquire them for a good portion of the game.
• If nothing else, maybe always allow buying them at the galactic bazaar for a high price. Right now the bazaar runs out of it too often to make it a reliable source.

UPDATE: I have softened my position on Techapods a bit, as I have at higher level play the module costs to be a big bottleneck, and so techapod access is not as big as I use to think. I still think Techapods are the strongest special resource, but I would no longer describe them as OP.

Tourism

• I feel like Tourism is a weird double-edged sword now.
• On the one hand, it is night and day easier to understand. Tourism has always been such a weird and fiddly concept. Now its has a clear and solid benefit.
• On the other, now that it now longer works off of your influence....influence is  weaker. And, I'm really not sure why tourism even exists anymore. If I want more money and influence....I'll go get money and influence buildings. I don't understand why a significant amount of techs and buildings exist around this yield, it seems so much cleaner to just toss it at this point.