Has the AI improved?
Yes, vastly. No, it isn't perfect, and yes, it will still have some moments that make you /facepalm.
Does it feel more like Civ (rather than CivRev)?
It never felt like CivRev to me. It felt like Civ, but unfinished. It feels more finished now - it's a valid, fun game. It does still have its issues.
Does it still cook graphics cardp)?
Only if you have a lousy graphics card.