Going into 1941, the Red Army had serious issues. While Richard Overy debates the number of officers actually having been purged in 1937-1938, the fact is that Stalin did kill, detain, or arrest a significant portion of the officer corps. What isn’t debatable is that the fear instilled by the purges hurt Soviet innovation and made officers reluctant to be bold and fight away from textbook tactics. It also increased the political intervention of the commissars in Red Army affairs, meaning that operational or tactical prowess was not always the determining factor of who was in command.
There are accounts from Catherine Merridale’s “Ivan’s War” of far too much political training for soldiers and not enough battlefield training. One commissar noted after the debacle against Finland that they needed to train the men to take cover under fire (page 79).
Add to that the expansion of the Red Army and you get an Army in flux with inadequate training and leadership going into 1941. The Soviets also has thousands of tanks, but many were light tanks like the BT series or T26. They were organized into large mechanized corps early on, which sounded like a good idea (look at German panzer armees after all), but the officers couldn’t manage them well. You get battles like Brody-Dubno where up to half the Soviet tanks don’t even reach the battlefield due to a lack of maintenance parts and support trucks. David Glantz found that one mechanized corps had only 12% of their trucks ready by Barbarossa. Officers often threw units in piecemeal as Soviet command and control was poor. Part of this was reliance on wired communication and a lack of radios.
The Soviet planes, while also numerous, were usually older and on hastily constructed airfields in the forward conquests that Stalin took before 1941. Pilots weren’t adequately trained due to post purge fear of losing aircraft in training.
The result is that a bloated and uncoordinated Army that was ill-trained and ill-led faced the Germans in 1941.
As losses mounted there were substantive changes. The Winter offensives of 1941-1942 saw some progress. Marshall Georgi Zhukov gave a series of orders trying to fix the command situation. He literally forbade frontal attacks and asked officers in writing to use ravines and try flanking. He specified that recon, air, and artillery should come before an attack with supporting artillery during. He envisioned specific shock armies used for attacks to overwhelm the enemy at the point of contact and ensure that the best supplied units were the ones used offensively. He even calculated the density of men, mortars, and cannons needed per kilometer for a successful offensive. All of this would lead one to believe that these were recognized deficits prior to this point.
So we see some transformation in 1942, but it wasn’t complete. Commissars still held more sway until Lev Mekhlis lost the Crimean peninsula. Believing trenches to be unnecessary and configuring his men to attack, Manstein caught him napping in May of 1942 with Operation Trappenjagd and took the peninsula. Stalin removed him, and we see that in the Summer of 1942 that the balance of commissar power stars to shift to regular officers, who are starting to gain more experience and Stalin was weeding through the poor ones.
That said, 1942 still showed major deficits. In Michael K. Jones “Stalingrad: How the Red Army Triumphed” Officer Anatoly Mereshko states that during the German Fall Blau offensive, Soviet counterattacks were still problematic. He states that while air and artillery cover were promised, they never came. The result was that the red flare would rise, infantry advanced to within 300 yards of the Germans, machine guns would slice through the men, the attack would stall, then the Soviets returned to starting positions with fewer men and tanks. David Glantz’s Stalingrad trilogy is chock full of terse Soviet reports of Summer attacks with “ill-defined attack axes” and “failure to properly reconnoiter” an area.
Men were also an issue in 1942 as well. The sad truth was that 1941 losses were so high that the actual rank and file men of 1942 were often an entirely new Red Army. Hard to gain veteran to with such high losses.
I know this was very focused on 1941-1942, but I hope you can see the issues the Soviets faced and how they worked on overcoming them.
Sources:
David Glantz “When Titans Clashed” - Zhukov’s orders.
David Glantz “Stalingrad Trilogy” - the best collection of Soviet archival material available easily in the West.
Catherine Merridale “Ivan’s War” - lots of primary accounts about problems in fighting or training, Soviet motivations, and general life during WWII.
Michael K. Jones “Stalingrad: How the Red Army Triumphed.” - accounts of failed Summer attacks in 1942. He would argue that Chuikov reinforced men’s trust in officers and led to innovations like defense in-depth, creating hard points, using small assault teams and sniperism as huge advances that prepped the Red Army for 1943, but I think he gives one man too much credit.
If you like crunchy books, try Alexander Hill “The Red Army.” It goes into a lot of depth on structural and training differences throughout Red Army history.
Richard Overy “Russia’s War.” - rethinks the purge and is worth reading. Short and visceral and I recommend it.
I see that 1941 has already been well covered. Here's a look at the material situation throughout the war from a similar question answered by /u/abrahamlincoln