What I'd like to see:
-More vehicles which are towable with medium sized helis like Hueys.
-Motorcycles: Hopefully a dirt bike, dual-sport, and cruiser for variety and so the code is there for modders. Maybe even a BMW R75 or Ural motorcycle with sidecar.
I'd love if they put in this new bike or something inspired by it:
-Bohemia Interactive crafted AR15 and AKM (perhaps also AR10 and AK74)
-Mac-10
-New code to prevent AI from seeing you right through foliage
-Some kind of trick to make all of that foliage look decent on medium settings without wrecking your frame rate ;)