Gus should have stayed good when he came back
I like the theory Drew had about what people where like before they died and how that might determine how they came back. See everyone prior to Gus being buried they was all good people that was buried and they came back evil. Gus however was evil before he was buried, so it had like an opposite effect on him, turning him good (well at least at firs).
I just wish he didn't eventually turn evil when he killed Clyde, it would have been interesting seeing someone actually be turned good from the burial ground. Say like if you're good when you're buried there it brings you back evil, but if you're evil when buried it brings you back good.
I just thought it was an interesting theory.
When Gotham is ashes... you have my permission to die. -Bane