1) An Army/USAF Mh-47G?
2) Mh-X Silent Hawk?
3) Afghanistan
4) Iraq
5) A large variety of attack aircraft armament (targeting pod of A-10C)
6) More rappelling capabilities (rappelling out of a chinook)
7) Better (AI) that may look more modernize (ex: not having helicopters) for the present day war
8) As mentioned before, better quality (graphics)
All in all, I think having the modern day war style would be awesome along with some of the future weapons/vehicles that are soon to come out. There's also much more but not going to mention them yet.