Where it provided an extremely unpleasant ride, inferior mobility compared to the medium tanks the allies fielded on both fronts, and, due to already being maxed out for weight bearing capacity, there's pretty much no further upgrade potential.K? It was used in that role though.
Again, fine as an interim solution, not ok on a new 1944 design.
Problem! The Germans in 1944 are keeping the IIIs and IVs in use because they can't produce their intended replacement fast enough to replace them all. While the III/IV maybe a wee bit easier the manufacture than the Panther, Germany still doesn't have the capacity to completely phase out the IIIs and IVs. So in reality it'd just add another separate logistics train to the Heer.One unified model, so no need for separate III or IV logistics train