I'd say that what happened in BG1 is that people filled in the blanks, and Bioware's sup par writing didn't really manage to shine through, so to speak.
And yes, I'd say Torment, Anachronox, MotB, and Fallout 2 had some interesting NPCs, and perhaps better than BG2's NPCs. AS for KOTOR2 while the characters were potentially interesting, most felt incomplete. KOTOR1's characters either made me want to kill small, cuddly animals or were ignorable. Whoever wrote Carth and Bastila should have their writing licence instantly revoked.