Small correction though, Panther can survive "only" 9 penetrating hits with all bonuses combined. Strong thing though is that you don't need the Command P4 close by all the time. You could wait until your Panther has eaten 7 shots, then drive it close and jump up to 9 shots.
The only drawback is that this build takes quite a while to get going. You basically need the Panther, Command P4 and at least a PWerfer for fencing off ATGs, better yet a Brummbar. Potentially you need to build a normal P4 for the mid game, which would put the game at the 30 min mark until you have everything together. On the positive side, you can create the build from a standard, unspecialized Ostheer one by just adding a Command P4 once the normal P4 dies.
"only" 9 shots equals to outsurviving allied heavy tanks and even the king tiger in terms of what you can sustain as punishment. actually, a veteran sturmtiger has only 40 more health points
1400 potential health for a tank is really strong + you also shield infantry with the aura + IT ALSO WORKS ON ALLIES. to top it off, hull down demounts instantly (letting you escape right away) and (I THINK) you get panzer tactician with it.
in team mode additionally you can reliably pull off this build, unless you are heavily losing (triple cap & both fuels lost.) axis teams simply need to get fuel caches and play the waiting game, and eventually overwhelm the allies with panther/arty spam