I think someone at GC2 has been playing my other favourite game - Space Empires.
In Space Empires you civ can only colonize planets with certain atmospheres - rock, gass or ice. This often makes you more friendly towards other civs who aren't competing for the same planets and adds a whole new dimension to things.
I think that it is absolutely Great that GC2 will be getting this in the expansion pack - a thousand thank you's!
However there is one thing that Space Empires still does better than GC2: fleets. In GC2 I can have about 6 huge ships at most, whereas in SE I like to eventually build fleets that have a large number of huge ships in them. To illustrate this - when I end a game in SE I usually have a two or three fleets each containing several hundred huge ships!
Please can the GC2 team allow us to build unlimited sized fleets - I want to have Babylon 5 style battles - not small Star Trek like skirmishes. It would be worth it even if it meant turning off the graphics bit and just seeing a graphical list of your fleets status at the end of each combat round.