Well, this is a hard question to answer because frankly there have been a lot of failed games through the years with absolutly ridiculous AI that can't even get from point A to point B when commanded to, and oftentimes even when taken by the hand. In comparison Dom (never played much Gears Of War 2 though), FPS "bots", or the much "vaunted" Sheeva (Resident Evil 5, heralded as some of the worst AI for the type of game ever) are amazing feats of programming in comparison.
The problem with me writing this though is that while I remember the problems, my brain has burned the titles out of my mind, probably due to trauma.
The big problem with AI though is that it's possible for people to program "godly" AI and then basically make it so the player feels irrelevent as well. I mean if you feel like your watching a computer vs. computer demo there is something wrong.
Those who have played fighting games can tell you that computers can simply react much, much, faster than any person can ever be. A fighting game could be created that is literally impossible against the AI, but what would the fun be?
>>>----Therumancer--->