From my perspective, what really makes Bully is the intense interaction with all the other characters, especially the other students. All the dialogue gives them a personality that is lacking in the majority of games out there. Manhunt has a lot of funny character comments (particularly in White Trash, my favorite), but everybody in the game is out to kill you....You can't just stand there and carry on small talk with them.
I would hope that is expanded in a Bully 2....Have Jimmy, (or whoever) equipped with a larger dialogue to carry on a more expanded conversation with the others, past the few lame comments he has now. Also, having other playable characters (aka Resident Evil) would be a plus, methinks.