Panthers were exceptionally mobile for their size and weight, because they had a big engine and wide tracks. With almost 14 HP/ton they had a higher top speed and probably better off-road performance than the Sherman (Firefly) at 12 HP/ton. And more than the IS-2 which had 13 HP/ton.
So even though historical accuracy is never leading in CoH, there certainly is some historical justification.
I honestly don't understand why people bring up historical accuracy into coh1. cus IRL the t34's had superb effective armor which is not the case in game.