How about no and you just position the damn thing right when you want to shoot a plane. You will be fine.
There is little reason for this particular vehicle to need more micro to counter planes and I guess it quite frustrating for less experience players to try to figure out why their AA vehicle does not
fire on planes.
Actually AA mode was available when the unit was introduced I really did not see any problem with it and nave no idea why it was removed in the first place (I am not sure but maybe it was simply removed because it was a vet 1 ability instead of becoming vet 0).
Finally as I explained by making this weapons separate one can balance them separately and it will not end being Up or Op when when they change (take for instance quad that is currently OP as an AA)
On more serious note, i feel like the supression on the move is actually fine in this case since its not 360 degree, and you have to put in quite a bit of effort of keeping the AA moving the right way. Unless you're a smart brain and have a key with reverse+click scripted on your mouse which makes reversing and using the AA significantly easier ^^
The unit can be quite frustrating to maneuver and reverse as toggle can probably help.