It's undeniable the game gives you a lot of choices leading to different paths/events, this makes the game replayable because it's likely people will want to play again and experience what they've missed the first time they played the game. I've completed the BG trilogy (yes because ToB is more than a simple expansion) at least 10 times so for me it's surely replayable but I also have to admit there was not the same amount of different paths possible backed into those games (BG2 is better in this respect than BG1 ofc).
