I REALLY hope that they correct the horrific vehicle physic from GTA IV. I know they were trying to make the handling more realistic but they took it too far. It felt like driving a top heavy boat around, completely ruined the experience for me.
I believe a 2012 release is most likely, maybe early 2013. While I did not like the gangsta vibe of San Andreas the trailer for GTA V blew my mind. And I am always open to having my opinions change, it has happen before. So here is to hoping it comes out in 2012.