I thought GRAW2 was there on the game play I thought it was great but lacked in key areas.
What I would like to see in GR-IV.....
More coop slots like WK said above
Better Script editor....simpler......no code writing......and stable would be nice.
Better simpler servers (deicated or hosting) none of this "/admin/login/map_01 or what ever it is that's weak.
I'd like to see kit selection in COOP like it was in the single player GRAW2 pick your pri, 2nd, nades, smoke ....
and support the game with patches and an expantion or two don't move straight to GR-V when this one hits the store shelves.