I remember hearing rumors that you may play as multiple characters throughout V. I hope it's true, that would be pretty damn awesome. Maybe once you beat it, you can choose who you wanna mess around with. My ultimate hope for this theory: You play as protagonists from past Grand Theft Auto's who end up coming together. That would be fucking incredible. Start as uh.. the GTAIII guy, transition to Tommy Vercetti, them Carl Johnson. Unfortunately not Niko, I remember hearing his voice actor left or some shit. I don't know, it seems unlikely, but would be amazing. The most likely thing, though, will just be a new character all together. As I've said before, I am SURE they will not recycle a protagonist, as they never have. I just don't see why they would unless they were to go with my "all past protagonists" idea.
Also, about the vehicles: Grand Theft Auto is the title of the series, they need to focus more on the vehicles. Realistic driving, (maybe have an option to toggle it, because simulation driving was fucking hard in Mafia II) realistic flying, including realistic crashes as stated earlier. I hate the "clip wing on tree, explode" thing. I'm sure they will change that, just like the helicopters in IV and how the blades and tail could get ripped off. It would just be cool to have a wing get ripped off and then try your hardest to crash land safely in a field.
Also, jetpack. I want my jetpack back.