What Axis players want is a vehicle that fulfills its AT role. Not a vehicle that counters one unit in the vehicle bracket and performs meh versus the others. It´s weakness (Ostheer one) is the lack of good AI. Better than what SU-85, Firely and Jackson have yet those have 60 range and are mobile AT guns.
The panzer IV is great AI and even more so at vet II.
When we look at a tank we should look not singularly at cost, penetration and AI, but the whole combination. Panther has excellent penetration, is as fast as t-34, has almost the same frontal armor as heavy tanks. the fact that it is adequate AI is just icing on the cake. And let us not forget that terrific vet 1 ability and vet 2 free armor.
It is a big investment, but one that will pay off significantly more than say a t-34/85 or EZ8 if it survives to vet, which with its speed and armor, should not be hard.