Germany had a general tendency to focus too much on new models with vastly greater capabilities rather than refine the exisiting ones. This might have been somewhat justified in the case of fighter planes (with the Bf-109, Germany had an adequate and competitive plane that was cheap and easy to produce. Working on something new and spectacular made sense if there was to be a research budget for fighter planes at all. On the other hand, funds blown on some of the more bizarre projects could have seen better use).
With tanks, however, this was a different matter. The 'bread-and-butter' PzKpfw 4 was more than adequate against anything on the western front, but the T-34 outperformed it and was fielded fielded in huge numbers. The Panther was possibly the best tank of WW2 after the reliability problems were reduced to a tolerable level but it never became the mainstay of the German tank forces. Tigers were inferior designs (mechanically demanding, expensive and underpowered) and rather heavier than needed with corresponding sacrifices in mobility.
I think many Americans overestimate the effectiveness of German tanks because, frankly, the US brought a dagger to a swordfight. American doctrine didn't call for tank-on-tank combat and the relatively light M4 was judged adequate for the roles required of it. Tank-on-tank combat, however, did happen.
Unless they significantly outnumbered German forces, the Shermans usually came off worse (on the other hand, later versions weren't the deathtraps that earned some very cynical nicknames).
All in all, I would rate the Soviet tank force above Germany's in most respects other than innovative tacts (and if we consider that... it could be argued that many of those can be traced to Charles de Gaulle), so having tanks as a German UU feels slightly off.