I was thinking about the new hand on hand fighting thing. Sounds alot like The Warriors. Grapples, throws, mounting fallen enemies. It probably wont be as complex as the Warriors. But expect something similar. But it only turns on when you have a Melee or No Weapon when you aim at somebody. God damn. I want to see a video of this fighting.
Edit: Just thinking some more. Rockstar seem to take stuff out of their other games and fit them into GTA.
Manhunt = Stealth Kills in San Andreas
The Warriors = Fighting Style in VCS
Bully = Going to school in GTA IV