There's no reason EZ8s should come any earlier in CPs than T34/85s.
There's no reason why the Ostheer Panther should have significantly worse stats even at vet0 than the OKW Panther, and the unit could use those stat buffs rather than the OKW version getting nerfed down to the Ostheer level.
OKW is supposed to have stronger, more expensive units.
Ostheer panther is weaker, but you also have all sorts of over medium tanks to support it. The support units for the OKW panther are much lighter vehicles. (flak track, panther, luchs)