First off, there definitely should be another Bully game. I doubt a direct sequel would work that well considering how well tied up the Bully story was, but a sequel like in the GTA series would probably fit quite nicely. College would also probably be a good cognate for private high schools, since it is a place you get sent far away from your parents, who may or may not be paying for it.
My main worry is that as the main character becomes legal age to do things which are illicit to show, those things' references will become more veiled. So now that the students can officially have sex, they wont be able to show it, whereas making out is standard TV fare and actually can occur on screen in Bully.
So, I worry that the dramatic tension will miss something. Regardless though, a sequel would rule.