BG2 NPCs are among the best I have seen, they are all so charming in their own way. The conversations in the game are smooth, often executed in a back and forth manner between PC and NPC, unlike most of the recent RPGs' NPCs which feel like information providers and generally less engaging. I admire the efforts they put into dialogs.
I guess many codexors prefer those intellectual subtle character that like to discuss philosophical problem with PC. This is not my favorite I have to admit, I think it's a very bad way to depict a character's personality and thoughts. I'd rather the character "live it out" her beliefs, by actions, comments on events or just casual banters. I think that's why BG2 feels so right to me. It's true that BG2 NPCs are over-done, they are dramatic, but that sets the tone, the NPCs fulfill the job perfectly. IMO there's no better or worse, whether a more realistic approach or almost comic book feel like BG2, it's just that a preference. Heck drama are... dramatic but they're still good art.