Customizable cars (at a price of course)but with this, you'd have to be able to recover your car where ever you left it, like put a little symbol on the map if you had to leave it for a mission, but if it gets destroyed, you lose it, if you get busted, it gets impounded and u gotta steal it back, or pay if you wanna do it that way
fully customizable, looks, performance, the whole thing
stats/skillsthe character is dynamic and changes depending on what u do, you can go to a gym, or if ur running/swimming a lot, he can get fitter/stronger, but if u drive allover, and have him eat a ton, he can get fatter
loads of guns, all kinds of all styles
source of income
either by properties(may or may not be gang related) or having a job(job is boring though)
more things to fly