If you've played PB2 enough, chances are there are elements of the game you're really fond of. Is there anything in PB2, whether it be in-game or within the level editor, that you would categorize as simply "perfect?"
Despite whatever flaws we may find with this now 10+ year old game, I'd love to shed some light on things you feel Eric truly nailed, and perhaps are things we can look forward to for PB3!
For me, I wouldn't change the self-boosting. It is so unique to this game... it even created a skill-gap and allowed for a lot of really creative maps. Even though it was apparently a mistake on Eric's part (self-boosting was never meant to be in the game), I think it's one of the most fun parts about the multiplayer experience!