That sounds like the best solution proposed yet
Yeah, it is hard to fight from inside a building.

Also, aircraft have restrictions, they must be on a runway (or GV base, it works but shouldn't), if they are in the grass next to a runway they still get a ditch. It is much easier to get a GV to a particular point, so having to be inside the vehicle hangar seems fair to me.
The defender in a Tiger II will still have the advantage as after losing his turret it will be a short drive back to his VH to tower.