Re: the situation in August 41.
I dug out Alan Clark's "Barbarossa", and here are some enlightening excerpts:
"Now followed an agonising period, two and a half weeks long, of interegnum. AGC, its leadership hamstrung, floundered on the brink of a tremendous opportunity, while opposite them, for nineteen perfect campaigning days, the Russians worked unmolested to rebuild their shattered front".
and later:
"For almost seventy miles along the Desna, (...) Timoshenko's defence can hardly be said to have existed at all."
"There was practically no artillery, and not a single tank in working order between Spas-Demiansk and Bryansk. The whole region was in anarchy."
Seventy miles arguably is a little narrow for a strategic offensive directed at Moscow but had the entire Army Group, after resting, worked at unhinging the Russian defenses along the Sozh or at Yelnia, it would have been easy to clear the way for a fullscale attack through the Roslavl gap. This would at least have been well within 2.PzGruppe's capabilities, had it not been diverted South. Besides, a large part of 3.PzGruppe's tank assets had been sent North to assist Leeb in assaulting Leningrad.
Or maybe is Clark's book a little outdated?