Mainly because I'm a defensive type of player. I need to cover everything, before advancing anywhere :) Also, the situation is not fluid, both sides sit in level 3 forts everywhere, except in the place that has 90% (or even more) of Axis mobile forces concentrated (first it was around Tula now Voronezh to Voroshilovgrad). Attacking there would be a suicide, due to powerful counterattack ability of massed panzers. Therefore I try to make defense there the strongest there to stall Axis advance. This makes it impossible to reinforce any other area to gain offensive capability. I need to have more corps to fight on even terms. Stacks of 3 divisions backed by even more stacks of 3 divisions are costly to the Soviets because of routs and retreat losses. I need to reduce counter density. Next reason - advancing in blizzard is hard - first it costs a lot of movment points, second the units won't dig in, and without digging in it's impossible to hold against a counterattack. Due to "passive" 42 (no units lost for both sides for the entire year), both armies are very strong. I am now coping with the massive surge in airforce size (regiments max size from 20 to 32) which created mess with plane pools. Due to vehicle shortage (since September) I can't build any mech, tank corps or artillery divisions. Also, my arm pool is at 0 now (because of the rifle squad mess).