I think there are several easy things to do that would 'fix' GVs, in my opinion.
1. Perk the Ostwind. When people 'but there is nothing to replace it', that isn't true. The M16 is also an AA platform. Of course, nobody uses it now because it cant kill people in one hit.
2. Remove the M8 and replace it with something useful, like a rock, or maybe a sheet of paper.
3. Weaken the M3 and M16 (for unarmored vehicles they are entirely too tough).
4. Make the Ostwind much easier to disable- that is an OPEN TURRET that gun is sitting in after all... and it wasn't remotely manned either.
5. Up the damage the Panzer does against buildings with HE rounds, and model one that has something slightly more effective at air defense than a single 7.92mm MG with limited traverse.
6. If for some reason, perking the Ostwind proves untenable, then lower the damage it does against other vehicles and buildings. It is supposed to be a mobile AA platform, not a roving destroyer-killer robot.
I'm seriously wondering why the M8 is in the game at all? What was HT and company thinking? Were they serious when they put this in? "Yea, lets put in a GV that every other GV can kill with ease. Wait.. even better than that, lets make it doesn't have a chance in hell of actually killing any of the other GVs either. Man, that'll be such a HOOT to drive around in!"
Drive an M8 for a couple days, you'll understand why I am 'whining'. I saw planes actually break off someones dead 6 to strafe me, because they knew I'm an easier kill than the plane is. That is truly pathetic.