I agree with more random events, I also want more customization for creating a race (more political parties and abilities foremost) and more ship styles.
List:
Things that weigh heavily upon my mind:
- More customization (Ie. more ship styles, abilities & parties).
- You decide how much money you start with (but not on the Metaverse).
- More things to manage (and by this, I mean things like adapting to planet's terrains and getting bonuses if youre particularily good at doing so, and asteroid belts of course).
- More options and stuff in Diplomacy.
Things that are pretty mandatory:
- Better combat viewer.
- Ships move kind of like in the Star Wars movies: currently they just either stand still and 'flip' around, be close to going through eachother and things like that. Have the fighters move fast and engage and move around the enemy ships and shooting with the capital ships forming a line behind or something... or even let you choose the formation.
Overall things I would look forward to in an expansion for a great game such as GalCiv2:
- More racial overall cuztomization (Priority 1, personally I would even play the game if you couldnt customize your race).
- Asteroid belts, special terrain types and stuff like that (Priority 2).
- ''Star Wars'' type of combat (Priority 3).
- Your continued listening to the customers, this is really great (Priority 4).
- MUUUUCH and I really mean MUUUCH more random events, everything from upon colonizing a planet to finding some artifact from when even the Precursors were kind of young, yes, seriously, the random events are about the third next to race customization and random events as to why I play this great game! INCREASE INCREASE INCREASE!!! AND vary!
- More ships classes! after a while, you simply decide that yes, you want that 500 space ship which is basically as large as a small country. (This would be really nice to see, but I give it a Priority 6).
Enuf' said

. Good luck with the expansion, you have our hopes!