Rich... again... I understand your point... but, it simply makes no sense to have a spot of "holy ground" where a tank can just magically land if they are under fire... and land their kills. Here is a scenario:
1) Wirble ups from the "sacred" tower pad.
2) Wirble sits on pad while popping planes that come in and try to take him out.
3) Wirble gets turreted
4) Wirble "lands" while surrounded by enemy planes and lands his kills.
5) Wirble reups at same pad and does it again...
Simply put, GV's in real life HAVE to get away from opponents and return to a safe area... one that is defended and in friendly territory in order for the crews to get home, get some chow, and brag about their kills. They dont hop out of their tanks in the middle of the battle zone, with enemy units all around them, and cry "Olly-olly-ox-in-free... I'm on base... you cant get me now!"
Fact is... GV's ARE at a disadvantage when compared to planes... as they should be. Air power is the biggest fear of a tank crew... or any ground unit for that matter.
What ground forces need to do is support each other. A tiger that rolls into a base alone to try and pop buildings deserves to get hammered... it was alone. But get your teammates to support you with flak, supplies, troops, and other tanks... and the tiger has a darn good chance of not only being a part of taking the base, but coming home if things get too bad... and doing so without a penalty.
I dont think there needs to be a huge change in how GV's disengage... but rather a change in the tactics GV'ers use to attack bases. Very rarely do I see actual coordinated ground attacks. Its usually one or two GV's making a full speed run on a base or town to try and take it down. If they get killed, they hop in another one and do it again. What needs to happen is for teams to plan a ground assault. Decide in advance how many of each GV type is going in, what the support units are going to be, and what the exit plan is. NO ONE ever has an exit plan.
And the same DOES apply to aircraft. In order for an aircraft to safely get home, they have to disengage, outrun their opponents, and land at a friendly base. Yes, aircraft are faster... but the principle is the same. You cant just bail in your 262 over enemy territory and get to land your kills, or keep your perks. Nor can you land a Tiger, surrounded by opponents, and get to do the same.
What DOES sound better, is a way as Ghosth mentioned for a GV driver to know when he is in a safe area, so he CAN land and get to keep his perks and his kills.