I just got Galciv2 gold, and after playing a few games I thought I'd share my thoughts with you all.
First impressions: Wow! The whole game feels so slick, graphics great, interface great, everything is so smooth I'll never be able to go back to SE5!
Second impression: I just got my ass handed to me by the AI, and it mocked me before doing so
Third impression: Ok, so there is some room for improvement after all. First of is the whole espionage stuff, it just doesn't work well. I need to spend a load of money to be able to see what’s on an enemy planet. Makes sense. Unless I want to place a spy there, suddenly it's for free! And it's so simplistic it doesn't actually add any strategic depth to the game IMO.
Second are the planetary improvements. The basics like factories etc. are all there but the special buildings seem a bit boring. All they do is add a few bonus percentages here and there. Even the trade goods and galactic achievements! Come to think of it, the racial traits and resources are also just % modifiers. All that stuff should give my empire something UNIQUE, not just a higher modifier on some statistic.
There is a few other small things but my biggest gripe with the game is actually the tech tree! It's so uninspired as to actually be detrimental to the game experience. It doesn't feel like I'm researching some exciting new technology, I'm just busy upgrading my statistics some more. Like there isn't enough bonus% going around with the resources, special buildings, etc. The ridiculous robot doesn't really help either. The campaign deals with heavy stuff like genocide, and my research robot sings me 'old McDonald had a farm' or says that it doesn't really know/care what we just discovered? Unfortunately just about every other game in the genre is a lot better than galciv2 with respects to the research tree. Go play some lost empires or SE5 stardock!
Anyway, just my opinions

Maybe I sound a bit critical, but that's just because I love the game so much!