we all know the ostwind, 251/17, and sturm tiger are what nearly won the war for the germans.
The Ostwind should have been a Wirbelwind, only because the Möbelwagen would need a set-up and tear-down time, which doesn't fit the role of a mobile anti-infantry weapon. Rather, it would be temporary static-defense.
251/17 should have been the 251/21 Drilling, but Drilling didn't need to 'setup' because it had fixed panels, so the unit would function more like the Soviet Quad, which may have been too similar.
The Sturmtiger gets a pass solely because there is nothing else like it that could take on the function it has in-game, but I still think it's a silly unit and hard to balance.
I have similar feelings about the Jagdtiger, would have preferred a Jagdpanther instead.