Nobody is saying such a nerf should come without a buff to Raketenwerfer. But your argumentation is extremely forced, think about the tank itself. Allies have a lot of problems on their own and their tank destroyers are still worse. Axis can do the AT without tanks far better because of Panzerschrecks.
Panther is overperforming. If an overperforming unit is nerfed properly, it becomes balanced, not useless.It would then still be built.
Bazooka is utterly useless and not even remotely decent even against Panzer IV. So "bazooka blob" is out of the question.
Panzer IV can fight Soviet tanks effectively and Jackson cannot brute force a Panzer IV with panzerschreck and stunning Pak40 around. It would be the same thing with Panther; you avoid the enemy tank, except Panzer IV stands a far better chance because Jackson is far worse than a Panther and Panzerschreck is far superior to something like PTRS or Bazooka.
If you want T3 to be used more , you should first admit that Panther is overperforming. You would then have a case to make Panzer IV better. As it stands you're supporting the notion that there's no way T3 should ever get a buff when Panther is so good.
The Panther isn't over preforming, rather, it is literally the only turret non-doc Axis tank in the game that we see built anymore thanks to a lack of options.
The Tiger is spammed because it is cheaper, the OKW Panther is often mandatory because of the non-viability of the Rackten and the fact the JPIV is extremely unmobile and lacks any kind of traversable gun.
The Zook is useless against the KT and Panther, but it does excellent DPS to the PIV, Ost, and StuG III. You would see more Zooks if you saw more Axis mediums, unfortunately they do not exist for OKW and are non-viable for Ostheer.
And I think the last Panther nerf can tell you were the unit will end up if it's nerfed; the garbage bin.