Panther needs a durability nerf if anything comes to its counterpart TDs.
My proposal would be:
Allies:
Decrease ROF for SU-85 and M36, perhaps decrease M36 HP to prevent diving with it.
Axis:
Decrease Panther HP to reduce its own durability in dives and the mitigate the near absolute requirement that allies build TDs specifically to counter this unit.
All sides:
("Super") Heavy tank call-ins require AT LEAST CP 12. Tigers, IS-2, Pershing, etc.
KV-1 and Churchill I'm less sure of.
IMO it is the Allied TDs making pather that big of a problem since OST doesn't have acces to a mobile 60 range AT platform. If we look at OKW it is fine with the JP4 anyways but for OST the current panther is a MUST with current allied TDs.
But you ideas are solid too anyways.