I think AI has become less of a focus due to the rise in MP vs SP for FPS games and the fact that it become standard not to have bots (bots in MP also drove quite a bit of focus on AI for PC MP titles).
It's a shame as great AI is vital to a title I think, and while most AI suffices I'm disappointed we haven't seen it pushed further. At least some titles, FEAR, Killzone, Halo, Gears, MGS, etc. seem to deliver good AI - although I agree the jumps in AI haven't kept pace overly with graphics, etc.
All games have quirks in AI, but I think Half Life and FEAR remain the best titles I've played in terms of AI.
I think Crysis AI is okay for the most part, and indeed the thing is so open ended (like Far Cry before it) that some silly stuff is always going to happen. For some reason Crytek always seem to focus on AI for on-foot and only ever seem to implement basic driving AI. Far Cry and Crysis contain some of the most amusing bad driving I've ever seen.
Try to be reasonable... its easier than you think...
