Only major complaints about NWN2 are:
that the companion influence system doesn't like evil characters, in general
too few new prestige classes, barely any new since NWN:HotU
the game eats harddrive space like no game I've ever seen before (friggin huge, especially if you count the size of the saves and the patching, which I suggest you do (patch that is))
Allthough there are more companions than in NWN, they still don't seem to like giving you evil NPC's (the few you get are introduced late on... thankfully, you get a CN early on)
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well, I suppose there are a few other things as well, but those are the ones that are the most trubbeling... it's still a great game, and I enjoy it more than the first one... feels more like you have some choice in where to go now... ofc, it's still no "Baldur's gate II: SoA" ^^
BORK!