Well from what I've read, GalCiv isn't SEIV with better diplomacy. Ship to ship combat, designing ships'll be less interesting. The diplomacy model seems to be leagues ahead of SEIV's though. None of that "Your growth is astonishing", and "Mineral planets are the best" crap
I also like the fact that it's possible to win without resorting to all-out force. No more Phong/Eee, partners for 5 years, all of a sudden declaring war on you just because you happen to have a higher score.
Reading the articles in the Encyclopedia section, and the game reports posted here should give you a decent idea of what the game's like. I liked what I read enough for me to (perhaps foolishly) be willing to purchase this game on faith
Below is a copy pasted blurb from the GoneGold forum. If you check the MOO3 forum, and do a search you should be able to find some GalCiv threads as well.
Copy pasted post by Edan over at GoneGold (March 3):
GalCiv (keep in mind, I haven't played in about a month, so a few things may have crept in.)
- dated graphics/music
- no tactical portion
- no designing of ships
- no multiplayer
-/+ Can only play human (but you can change some settings to make it diversified)
-/+ Random positioning (which can effect your chancs in the game.
-/+ Only looked a little bit at the Galciv forums, and they seemed active.
-/+ Theres a UN (or whatever) along the lines of the one in MOO3, but it's a lot less ambitious (pretty much, you just meet from time to time to vote on some referendum, and you're always in the senate, even if not everyone else is)
+ a number of ways to win (ie, conflict, greatest influence, etc)
+ intuitive/easy to learn interface
+ few bugs
+ balanced well
+ government system (ie, if you have a democracy, you have a senate consisting of 8 parties. If you don't have the most members, you lose bonuses)
+ very good AI
+ 5 map sizes, with the largest being very large.