The so called "Great Purge" during 1936-1938 in the Soviet Union is generally stated as one of the reasons for the losses that the Soviets faced during the early stages of Barbarossa. A significant amount of the Soviet officer class were killed, imprisoned, sent into labor camps etc. and commissars were attached to individual units that held roughly the same power as the officers themselves, both of which reduced the effectiveness of the Red Army. The purge also removed a good amount of the men that were supposed to train new officers, so the act of training and replacing was further slowed.
However, many will state that the Officer purge was not damaging at all to the Red Army and actually made it vastly Superior since many of the officers "couldn't" be trained in the new tactics and so had to be removed for the new tactics that modern warfare called for to be implemented into the army.
What are your thoughts?