And how is a soviet player fielding a heavy before you can field a panther? who said anything about making paks completely ineffective against soviet heavies? They are already more effective against tanks than a SU-85. Maybe it should be harder to beat a soviet heavy than just fielding one pak40, similar to how soviets need more than just a zis to beat an axis heavy.
Because thats how the current meta works. Soviets forego teching and wait till they have access to 85,is2 or kv1's. This gives them a rather huge mp and fuel advantage.
Simply put teching up to tier 3 or 4 as ostheer is suicidal. even if you get tanks out they will be of significant lower quality in the case of tier 3. p4 vs 85 is a lopsided affair in favour for the 85. in the case of tier 4 your panther will be outnumbered 3 to 1.
Now the allies on the other hand can tech up and get some very good TD's in form of the su85 and jackson not to mention their medium tank callins are nearly as powerful their td's.