I wanna see them take full atvantage of the Cheif's abilities.
-They should make him able to weild weapons that no other normal humans can't handle, (except Shack) like two rocket launchers.
-Basically, more feats of super-strength on the cheif's part.
-The ability to rescue fallen comrads
-A new BFG
-Waaay more guns and Vehicles
Mix that in with an already great formula, and you'll have the greatest FPS ever.