Redbeard
Banned
There's an advantage of attacker and Soviets were very big on "deep operations". Even most stupid and rigid Red Army operation is bound to destroy everything between Bug and Vistula before being bogged down by it's own weight.
There is no universal advantage of the attacker. An attack usually is necessary to achieve a decisive victory, but it might also be the main waypoint on the shortest road to a decisive defeat.
After the Spanish Civil War the deep operations doctrine, armoured corps etc. were abandoned, it was thought that the war had proved that a detailed distribution of armour among the infantry units was superior. When that transformation had just been completed came the Germans rolling over the French in May-June 40 and the deep operations incl. armoured corps were ordered to be reinstated. This happened alongside a huge expansion plan and by 1941 the result was utter chaos in the Red Army.
A large part of the staff, field (major-colonel) and general grade positions were vacant, and those in place were often totally inexperienced. On top of that much materiel was in bad maintenance, new equipment was expected soon, and in order to fulfill the high priority orders to reinstate the armoured corps most trucks and tractors had been stripped from the artillery units elsewhere. That was a major factor behind so many Soviet guns being captured by the Germans in 1941.
This also means that a Soviet attack in 1941 most likely would have been a number of armoured columns bogging down as they moved out of support range from the initial positions. Initially that would of course create some chaos in German ranks, but by 1941 the Wehrmacht was too flexible and swift reacting to collapse under the pressure. Some of the forward infantry Divisions will suffer heavy casualties, but they will be relatively easy to replace, and when the panzer groups go on the offensive, only stationary Soviet units will be there to defend and the Germans probably won't need to shift panzer groups between armygroups to deal with perceived Soviet concentrations.
An attack in spring 41 will btw be handicapped by heavy rainfall, but when the ground is dry by mid June, the Germans have dealt with a large part of the total Soviet war capacity than in OTL June 41, and so have a greater chance of reaching Moscow before the rain sets in again in mid October.
Regards
Steffen Redbeard