I sense a glaring contradiction here.
The main problem in AH is not the damage modelling... its the gameplay. A panzer is toast now because it is always deep in enemy territory with little to no air cover. That panzer would always be dead in real life no matter what penetration data said.
Why would making the Panzer impervious to only three gun types(30calibre/7.92mm, 50calibre/13mm, and 20mm) open the door for the use of Panzers as a "drive right up to your field" vehicle?
A Panzer will be deep inside enemy territory with shallow air cover just the same, but only to specific gun types it is granted immunity.
Then, if it were so, why would it suddenly change the Panzer into something monstrous like that when the main reason for the weakness of Panzer you have stated - "enemy air cover" - is still present? Unless, perhaps the real strength of the 'air cover' in AH is within its ability to strafe, not of bomb or rocket??
If you really believe in what you have said, ironically, it actually demonstrates the point that the most formiddable air-to-ground weaponery an aircraft would use against GVs in AH is not bombs nor rockets, not heavy anti-tank cannons, but plain MGs and 20mm cannons.
Why else would granting immunity to those weapons change the Panzer so much when the ability of the rockets and bombs to destroy tanks are all still there? You have cleverly avoided the point by stating "That panzer would always be dead in real life no matter what penetration data said." Of course, that is so true - without referring to
"what was the real reason behind the destruction of the tank in generality" that is.
Yes small numbers of tanks would have been dead in real life, just as in AH. But was it be because some desperate guy in a fighter strafed a Panzer from the side at low speed low angles and knocked out vital parts? Or was it because of organized air-to-ground strikes volleying loads of rockets and bombs in a deadly manner?
There is a big difference in these two which just cannot be 'skipped without mentioning'. I don't think even you are willing to refute the fact that strafing tanks were hugely inefficient way to attack in real-life, no matter what the possibility of penetration is.
If so, would a "concession that portrays the very inefficiency up to utmost maximum" not be better than the "pseudo-reality modelled by a data chart which seems to brings out the exact opposite results of what it was like in real-life"?

Would a "concession that encourages people to use specialized planes fit for the task they choose" not be better than every fighter plane being valid for the task and thus rendering the specialized planes useless?
What exactly have the people got to lose here?
Logically, there is no reason the Panzer would be able to just barge through every defense line even if it is granted some sort of immunity. After all, there are always planes with rockets and bombs, and specialized aircraft designed for the very purpose of strafing tanks. What the defending fighters won't be able to do is strafe every Panzer they see and knock the parts out and render it completely uselss. If they want to do that, they would either have to up an IL-2 or maybe a soon-to-com plane like a Stuka.
In short, there is nothing to lose, except the fact a plane lightly armed for A2A purpose won't be able to just discover a tank, go down and strafe it until it starts smoking.
Would it not be better off to lose that kind of strange fact exclusive in AH universe? Where people rely on mainly on small calibre guns to kill armoured vehicles?