Heavy crush help with the mobility of a unit since it can crush some objects instead of going around them.
I know that, but why only this MEDIUM tank.
No, the M10 has medium crush, meaning that it cannot break hedges and tank traps.
As to the question of the thread, I sadly do not know the answer but the panther also used to have heavy crush in coh1 (if I remember correctly), so that might be why. Due to its armour and the health bonuses at vet 2 it comes very close to a heavy tank.
The pershing is another medium tank with heavy crush.
Comet, oddly, even though it is somewhat similar to the panther doesn't. So there is no clear distinction as to what medium tank does get heavy crush.
That's what i meant (why is the Panther the only one in the game).
I guess only Relic knows !?!?!?