I recall the controversy many years ago when a popular shooter franchise (Quake? I don't remember) increased its difficulty by letting the AI see through walls, so te game always knew your location all of the time, but you didn't know theirs unless you had a line of sight.
A level playing field requires that the computer's reaction time be retarded to match that of the player. This is partly why I like turn-based strategy games more than real-time strategy games.
This is a problem with stealth in a lot of games too (in non-stealth games, that is, like ME2 for an Infiltrator).
I've just been playing ME2 again (such a good game), and I was just on Jack's recruitment mission. I was facing a YMIR mech. It was getting a little too close for comfort--actually, a LOT too close for comfort, so I used Tactical Cloak and starting backing up. About a half-second after I used Cloak, the mech began the animation for shooting a missile at me. I was expecting the missile to go right by me, but it slammed right into me.
Now, of course we could argue I was exuding heat, but that's clearly not a part of gameplay design--the fact is, the enemy is programmed to know where you are.
AI could use a serious, serious overhaul, across all games, not just RPGs. The problem is, I think, that it's so incredibly taxing. So many systems would be necessary for something even approaching believability (sp?).