Just buffing the ATG penetrations while lowering TD penetrations is also a solution IMO. (Except panther since it “must” fight allied heavies and flamehrowing tanks with high armor values thus it needs a cost increase to 200. For my other suggestion see my page 1 post)
If you want ATGs to be relevant then we will need to change the walking stuka as that thing simply destroys support weapons.
I would much rather see the game focus about medium tank and ATG play as the main meat of armour play. With less focus on panthers and TDs.