Well it appeared to me the slower the Blitzkrieg was advancing, the less effective the Wehrmacht was…
So if I was a Field Marshall, I would have let my armored spearheads advance all the way to Moscow, deploying a small force of less important units to contain the defenders, while the main spearhead captured Moscow, or destroyed or encircle the Red Army… Then focus on the defenders in Stalingrad and Leningrad…

Well the T-34/76 is widely regarded as the best tank of WWII. What do you think?