More often than not, they seem to be aware of where my party is, even if they shouldn't. If my thief goes ahead, backstabs someone, and runs away, they follow him for a while, but once he gets around the corner and hides in shadows, they stop in their tracks, and head straight to the rest of my group even if they didn't see them, even if they're on a compeletely different floor or something. They sometimes even ignore my warriors, despite being directly in their line of sight and doing a good job in hacking them to pieces, instead going straight to my mage that's hiding around the corner.
I like that the enemies are smarter these days, but they shouldn't be able to do stuff like this. It's both annoying and unrealistic, and I'm kinda against both of those.
In other news, there's one thing about the AI of my own characters that's been bugging me as long as I've played Baldur's Gate, and since this post is about intelligence in general and this mod seems to be doing a very good job with it, I'm going to mention it here now. See, those characters are always really dumb when it comes to ranged attacks. Please direct your attention to the elegant and well-drawn illustration here:
My archer, or a wizard (point A) wishes to attack an enemy fighter (point B), a killing machine in close combat but with no ranged capabilities. My fellow doesn't have a direct line of sight, so when I direct him to attack the enemy, he stupidly heads straight to the middle of it (point C), instead of trying to keep his distance (point D). Many deaths have come to me directly from the stupidity of my own characters, especially in the situations where I can't be sure of whether they see the enemy or now: And instead of taking one step to the right to see the enemy beyond that pillar, they walk straight over there and get slaughtered. I don't think this is so hard-coded to the engine that it couldn't be changed.
And one more thing, this one about the enemy intelligence: Why would a genius wizard sit on his butt in a corrosive cloud of Cloudkill, or sticky web of Web, instead of trying to find his way out? I mean, it just doesn't make sense, now does it. I could imagine some stupid animal or mindless undead to stand right there, but I'd expect humans and other intelligent creatures to try and find their way out of the thing, or even investigate and discover the nasty adventurer bugger who put that Cloudkill there in the first place.