This was a meandering affair ranging over several topics.

Q: Mud didn't slow Soviets in 1944. Why not?
A: American four-wheel drive Studebaker trucks could keep moving.

Q: Why were German Panzers ineffective in '44 and '45?
A: By 1944, the German panzer divisions were so worn, they could not contain all the Soviet attacks. They might stop three or four in a sector, but the fifth would undoubtedly succeed.

Q: Re: the Poland 1944 and Warsaw uprising. Why did the Soviets stop?
A: Politics aside, there was an attempt to grab Warsaw after the Soviets had seized bridgeheads north and south of the city. It started with an unsupported tank corps and ended with a sharp German counterattack that destroyed 90% of the Soviet tank corps. The Soviets stopped so logistics could catch up. In general, the Soviets needed two to three months to gear up for an offensive.

Q: Pripyet Marshes. What was the terrain like?
A: A marsh, but a very expansive one. Soviet territory is mostly flat, with sluggish rivers. As a result, swamps form on either side of these wide rivers. The Pripyet Marshes were a particularly low point and a particularly wide swamp. On a related terrain note: Soviet forests were often primeval--dense undergrowth and thick canopy.

Q: Soviet Mobilization in 1945?
A: The only units the Soviets were raising at war's end were Anti-Aircraft and Anti-Tank. The question then becomes...to fight what? The Luftwaffe was a non-entity and the Panzers were only a pale reminder of its once mighty self. Ditto for the Japanese. The answer has to be the US and Western Allies, not so much in awe of the Sherman tank, but the air forces.

Lectures

WWII Soviet Units Raised by Charles Sharp
Panel Discussion: 1944-45 by all
Sedan, France 1940 by Jon House