A Christmas Surprise for Army Group Center
Faced with such ragtag opposition and with 3 panzer groups at its disposal, Army Group Center could not resist a larger offensive in the direction of Moscow and we were not disappointed. On Christmas Day, tanks from Guderian's 1st Panzer Group roll into Red Square unopposed:

What began as a quick-grab encirclement operation between 1st and 5th Panzer Groups quickly morphed into a mad dash to the Soviet capital. It quickly became obvious that the Soviets had nothing in reserve, and no defenses in depth at all in this sector. Once 1st Panzer Group made the initial breakthrough, it encountered little resistance all the way to Red Square.
Only a single disorganized Soviet motorized division stands in the way of the link-up between 5th and 1st Panzer Groups, so this should be completed before the new year. This link-up will trap 14 enemy divisions in a pocket centered around Kalinin. Once this pocket is reduced, it will probably be the end of organized resistance in Army Group Center's area of operations.

Army Group North finds itself confronted with a similarly poor level of resistance, with just six Soviet divisions opposing it:

The southern sector is by far the largest in terms of square mileage, so there are more enemy units to be found there. However the panzers enjoy a similar freedom of movement. 3rd Panzer Group heads southeast toward Rostov, which will be the anchor point for a future offensive into the lower Caucasus region. The rich oil fields there will bring the Reich a step closer to resource independence.
4th Panzer Group also drives toward the Black Sea to isolate enemy units away from the industrial center at Stalino:

It may make sense to send Rommel's panzer group headed back in a northern direction, as a sizeable salient is developing in the Kursk area. With Army Group Center currently holding 2nd Panzer Group in reserve, mobile units are available to initiate the southerly push to complete that encirclement.