The best solution would be a punishment system. A Simple menu with like; explode, disarm, take money etc...
Imo helikillers are more annoying than drive-byers, heli's health seem way more than cars/bikes, especially if they lag like Cheetos.
Fighting at nam versus like 10 players, you don't have the fucking time to look after blips indicating that they're heli's?
The heli just comes down and takes like 4 fighters with it. I don't mind heli's, nor DB'ers if I'm not in a fight already.
Having all that said, make some sort of non heli/db allowance near nam.. That would probably be the best option.