Let different races prefer different planets

I like this idea very much! +1 from me.

I would love to see something like this. Possibly even a few more choices - volcanic worlds, gas giant stations, desert worlds,  barren worlds, jungles, metal worlds...

Indeed,this would add a lot of strategic possibilities in the game. Love this idea too!

+1 for me too

The reason I'm very skeptical to this proposal is that I want hard competition for the planets. I fear it wouldn't be if all the factions prefered different planets. The gameplay would suffer alot if that was the end result, and I can't see what there is that should make the suggested system more strategical. I forsee a less strategical game. Just saying.

This is similiar to what is found in Distant Worlds. Its an ok idea but Norseman is correct on limiting how the AI would seek planets. If there was a flavor of one planet over the other of two that are available ok, but only if the AI does not gimp itself....

choosing a Jungle class 5 over a continental Class 15 is silly....

+1 from me too, current system is nothing more then just factions in competiotion

Having some races start with the requisite techs to colonize some extreme planets is enough.  Competition occurs when species occupy the same niche.  This suggestion gets away from that.

Space Empires 3,4,5 have always had this.  3 planet types (rock, ice, gas) x 6 atmospheres (including "None", for which you can actually design a custom race of robots that "breathes" it and implodes under any kind of gas atmosphere ... uh huh.)

This has inscrutable effect on game play.  The possibility exists (like a half-remembered dream) that you could ally with your first 5 alien AI neighbors if they happen to breathe different atmospheres, and jointly become a 6-headed uber-faction.  Then you'd jointly crush away the chaff races 6-on-1, until you finally encounter an opposing clique-of-6 that can stand up to you.  Conversely, if your first 2 neighbors share your type/atmosphere pair ... then all 3 of you are the chaff, and you might as well quit and restart before some clique-of-4 crushes you all like bugs.  But SE* diplomacy is so impoverished that this arch-strategy never actually emerges in real play.  It's faster to just conquer everybody else regardless, then use their captive populations and stolen colony ships to settle those planets yourself.

Let's call this strategy the co-breathing clique.  If diplomacy were perfect and races were rational, and assuming enough time for the emergent strategy of "cooperate if we can" to emerge through open competition (i.e. by consistently winning vs. all other strategies), then the existence of this strategy reduces games to a bully's sandbox, with the bad rule of largest clique wins.  Then games are decided by map setup lottery: either your neighbors can co-exist alongside you, or they must compete with you.

This is maybe an unintended consequence of fabricating "more competition" in the name of richness.  If it actually enables both cooperation and competition, then you've got all the elements needed to embed classic Prisoners' Dilemmas problems (plural for the n > 2 case :)).  Every diplomatic grand-level choice becomes "cooperate or compete?" (collude or betray).  Then elementary game theory shows that the arch-strategy is something like Tit-for-Tat: always cooperate first, then do what he did last time.  Then cliques can arise through mutual cooperation, and ... largest clique wins.  That's potentially unfair in not-fun ways.

GC3's all-planets-same-type model neatly sidesteps this issue by making everybody a clique-of-1.  More practically, GC3 diplomacy already looks like a full job to code and script.  Adding the possibility of negotiating a symbiosis (joint empire, based on planet-sharing) might drive the poor devs bonkers.

I dislike the idea of modifying the planet class by a habitability index. Planet class has always seemed more likely to be related to usable landmass than actual habitability despite the game's claims that class 26 worlds are "like heaven" and class 4 worlds are hell, as habitability doesn't have all that much to do with whether or not I can build something on its surface. However, something that a habitability index would be useful for is as a modifier for the maximum population, the maintenance costs, or the happiness of the world in question. I would further submit that these three candidates for modification by a habitability index are more appropriate than planet class as they are things that the player can attempt to counteract if he or she chooses to do so - I can build extra entertainment centers or farms or markets and play around with the wealth setting of the planet to influence the population cap, the planetary approval rating, and the net income of the world. There's little that I can do to counteract penalties to planet class.

I would further add that a penalty to planet class based on the founding species of your empire makes little sense as a determinant of the actual planet class. Maybe you believe that all 8 billion inhabitants of those planets you invaded were put to the sword and that there's no such thing as resident aliens or immigration, or maybe you believe that citizenship is never granted to non-founding species residents on any planet (since planetary population is not the total population but rather the number of your citizens residing there, according to how it was handled in the game lore for GCII), but I don't. This argument is also an argument against penalties to population, approval, and maintenance, but at least with population and approval you can argue that aliens (i.e. members of species other than the founding species of your empire) are less likely to be citizens of your empire and less likely to be entirely happy under your rule, and so planets which are less hospitable for your empire's founding species are likely to have a higher fraction of noncitizens and dissidents. It's a lot harder to use this argument to support the idea that large portions of a planet's surface will become completely unusable based merely on who owns the planet.

I like the idea if you take the size of the planet off the table for an optional game. I don't like the tile idea for colonization. I would rather like a combination of the city screens for call to power and civilization instead with citizen management included. For planet class we could use joeballs idea with resources to enhance it.

That's how it worked in GalCiv 1.

PQ 15 was average, and the lowest you should aim for initially. PQ 14-10 required life support systems, which costs 5bc to maintain. PQ 9 and lower cost you 5bc for the life support, plus another 10bc per level of government (Imperial is 1, Republic is 2, Democracy is 3, and Federation is 4). A PQ 4 planet would cost you 15-45bc per turn just for colonising it.

PQ also determined pretty much everything for a planet: max population, pop. growth, approval, max tax income, max production and research, and max bonus production and research. A low PQ planet will always suck, and be a huge burden on your empire. Even after terraforming it. Unlike in GalCiv 2 and 3, where terraforming can turn those planets into decent, if not even great, worlds.

In SEV I would work on making a solar system with multiple races.

Good for Allies but if things sour then someonwe will be very unhappy very fast.

A way to add to stratagy planning only if one wants to.

To protect against the problems of multi civ systems make a system closed after colonizing one planet.

In GalCiv3 there is no way for a multi-civ-system. Ok, you can divide planets, but instantly the most populated civ will take over the others. Before we could think about different enviromental planets, this part should get fixed. I'd suggest to denie takeovers till the diplomatic situation is worse then 'neutral'.  

Systems are made of many planets.

I have already had times where one planet is me and another is someone else in the same system.

This is what I am talking about.

With the number of planets that some stars have you could make a system as the meeting place for your friends.

Of course you would not want to culture flip any of them.

And as a meeting place if made could add a % to diplomacy or something for those civs.

I wouldn't want a game that the star system was automatically closed to other factions just because you were their first. You would have to at least have an even number of all planet types to make this work. I don't really see much a difference game wise than the current system where you can have multiple factions in a solar system. Influence might be a little important. I also would like to see a astrobiological molecular description on each faction. This would be a good option on the game to pick from. We also should randomise the starting class of the planets and the other planets in the solar system.

In space empires they are only close to you at start. You can research the technology needed to survive and prosper on worlds that are hostile to your species, I never did understand the limiting of humans to only rock, since we are capable of having colonies on the poles and on the moon if we really want to support them, but I know it is a game balance mechanism. The same type of system could be employed here, I would think.

There is always a balance beten realism and the needs of the game.  moo3 for instance tried to modal different races liking different worlds. While probably more realistic it didn't really add anything and cut down competition for planets the major resource that drives conflict in space 4x games.

I like the concept very much and it worked well in MOO2.  It gave verity to the game and aliens were well alien.   AS far as this 'balance' argument goes I say to hell with it.  Remember you can create more races and if this is in the game then you will be able to select their home environment so you can create multiple races with same environment if you want.  Besides if they went this route I'm sure there will be races needed the same types of planets. 

I just read my previous post and realised to tell you I like the idea. The only game mechanic I disagree with is the preference for small planets unless they could use small planets just as good. But if they could use small planets just as good then they are penalised for big planets. I like the idea of preferring diferent planets.