Tweak the helicopter spawns, remove ability to repair helicopters from inside.
I've noticed helicopters in the sky are absolutely rampant! Making it near impossible to do anything when you have two or three enemy helicopters each with two guns I had gunners, and people constantly repairing them, and what seems to be unlimited flares! I've seen people pretty consistently in them the entire match going 30 to 50 kills to one or two deaths! Many of those matches resulted in people just quitting.