I see a lot of people complaining about the survivability of vehicles and a lot of discussion around this mechanic of the game.
As others have mentioned, the APC needs a rework seriously. Having 1 guy in the vehicle is counter productive as these guys are looking for killzones, and then sit until an RPG takes them out.
BF3 had a great vehicle system, with upgrades/loadouts. Reactive armour, thermal smoke, oil cooled barrel etc etc.
we need stingers for airships.
we need helis that shoot rockets (attack choppers)
main bases need AA.
all of this could be introduced and balanced accordingly.
adding more vehicles like in BF3 with MLRS (HIMARS) trucks (with the loadout option for anti vehicle or anti infantry rockets)
infantry mortars
1 commander per team, can coordinate all squads, has a drone for spotting (increase spot bonus for drones!!!!!!) And perhaps artillery with a long cooldown
What aircraft may be added, or not..?