I am not comparing them directly. Only stating the differences. A fast durable tank needs a weakness or area its less good at. Naturaly that would be acc or low rof.
I you wont notice the acc buff why does it need to get it?
The panther is already consistent in that no med has a chance vs it. Only td's and max range and super heavies do.
Its natular weakness is its advantages, in other words the fact that it needs to be exposed to the enemy and do risky moves in order to be effective. It it was an all-rounder tank like comet, then yes.
Panther has its health pool and armor, not because "yolo german engineering", but because of the way its designed to be played.
Other TDs are ment for defensive and supportive play, if you try playing defensively with panther, you would have a dead weight on your shoulders.
And speaking of the change. Basic acc buff aimed at situations where it shouldn't really miss, considering its role in the game. Basically to lower chance of BS situations happening.
Veterancy buff is there, because all other TDs on their vet 2 get penetration buffs to imporove their area of usage, panther gets vet 2 acc buff to improve its area of usage as a hit-and-run TD.