I was thinking about what it was about Galactic Civilizations II that I haven't really seen here that I miss.

I really enjoy the well scripted replies from GalCiv II!  The Snathi saying "don't hurt us", the Terrans with their 'What's up?", etc.  I'm sure the developers will flesh this out in Elemental as work on the game continues. 

I'm less likely to simply annihilate the minor guys if there's a reason to keep them around.  Decent interaction via Diplomacy, and the occasional humourous responses is why the minors tend to stick around for a while in my GalCiv II games. That and having sellers/buyers for the tech I want to exchange.

Gotta luv it when the GalCivII AI isn't interested in selling a tech:

"Let me put it this way.  Not gonna happen!"