Bring the airstrikes back and nerf the firebase's damage. The airtrikes were never really a problem but jesus that firebase is ridiculous, and this is coming from someone who plays support quite a bit.
Firebases are easy peasy to get rid of. Any tank can do it. As a gunner you just need to spin up the barrels, pop in front of it and BAM. Toasted steel. As an assault you can usually get an angle to bounce grenades off of and either use the grenade to help take it down, use it to bounce the support away from the FB or keep it around you to push the Italian away when he comes screaming at you. I used to think they were an issue but I don't really think of them as much of a threat anymore :shrug:
I use the firebase a lot to protect my turrets. I think nerfing it would be bad. If it isn't broke, don't fix it.