A couple of things I have read and learnt during the years:
1. As the German thrust pointed towards Kiev the Soviets had time to make a huge defensive position in front of AGC. However, the attack of Guderianīs troops from the flank came as a huge surprise and allowed the huge pocket be formed at Byansk-Vyazma with the capture of some 500-600,000 POWīs. Guderianīs operation started some days earlier as the main operation. Without Guderianīs separate attack the Typhoon might have not gotten far at all.
Battle of Moscow
2. The Germans did not only concentrate their attacks on Moscow alone as we ( or me only ) like to think. The Forczyk book mentions that also several operations were going on in the AGCīs area towards north and south-east probably in order to secure the flanks. The author considers many of these operations worthless as the main battle was being fought in front of Moscow. These operations were planned by Hitler and OKH. Which to me seems Hitler never realized the dangers he was facing as he was at the same time making plans for "minor" operations as there was a battle for Moscow going on. In the future I intend on finding figures on men and vehicles used in the ops going away from Moscow.
Just some ideas from books....