I think folks need to “let go” of the knee jerk reaction to call nerf.
There are two parts to how the Soviets or the Germans perform in the Moscow Campaign.
Firstly, the implementation of historically accurate equipment be they small arms or vehicles.
Secondly, the adaptation of these to a “game” so that there is a relative parity of both sides - something that most WWII FPS games struggle because there are so many variables to consider.
In this case Gaijin devs have implemented a “relatively” historical equipment line up, and have created an ahistorical squad make up for the purpose of abstracting that player parity - so you have a mirror image assaulter squad, engineer squad, radio squad etc… Only the weapon characteristics differ, and even then not by much, but as long as they are historically accurate I don’t mind.
What is becoming an issue is the growing imbalance creeping in from poorly educated Devs who are inconsistent in applying historical materiel vs the specific period of context for a given campaign. There is a bit of room to maneouvre here so picking the most prevalent vehicle or equipment type for the period would be desirable.
Overall this is actually in place, it just happens to be stretched out over the course of the campaign, but if we consider the Moscow Campaign, by level 29 most players will actually have a reasonably historically accurate line up (as long as they dump the gimmick weapons) and equip their soldiers accordingly.
Now, where the issues of balance begin is in the types of weapons available in the campaigns and their implementation into the progression line.
So first and foremost, there are too many SMGs and Automatics, for what was historically available, and some of the squad options need a little adjustment as well. The first of these is the MG squad which provides for 3 LMGs or the premium 4 man LMG squad - these are an issue and are ahistorical. Most squads had one and at most 2 LMGs as was the case for the German Panzer Grenadiers which appear post the 1942 re-org. So that should be adjusted sooner rather than later.
Similarly the number of SMGs available in game is excessive, The Soviets had the PPD, but it was expensive to manufacture because of its milled parts and quite inaccurate due to the lack of a gas compensator which caused the barrel to rise when fired. It was economised via a stamp metal manufacture of the PPSh which was also 70% more accurate due to the inclusion of said gas compensator. So the key issue here is which weapons are actually modelled, and if it is the PPD then its 70% too accurate and if it the PPSh then there are too many in game since only a few hundred were actually manufactured by the Battle of Moscow. Either way there should be some consideration given to the number of SMGs in game for a given player - ie maybe limit the SMG squad to one regular and one premium in the line up, noting that you can chose between the std and premium options and even that is a lot, so maybe chose just one. It’s also noteworthy that you can effectively create NCOs for your other squads by selecting the assaulter role in the squad progression tree which is a nice move and does infact create the historical feel of squad leaders armed with SMGs. In that context perhaps a reduction of SMG squads to one - take your pick std or premium might be appropriate. A tweaking of all squads to account for these sorts of weapon issue and roles might be considered along with a size expansion to their historical squad sizes, although by and large the Devs are already tracking on this - eg limit of sniper squad to a 5 man groupping.
The damage per round for the PPDs is 5.5 in the base weapon which is comparable to the 5.7 of the German MP’s and shows that the devs have taken the caliber into consideration. This can increase with weapon quality which is the same for both sides and is a reasonable game abstraction.
The Soviet tanks are accurate for the period, the German ones are not initially, but end up with the right models in the end. It’s a point of friction with Campaign accuracy, the Germans should perhaps start with the PzII, then have the Pz35t (since the 38t is premium) and then move to the PzIII F and PzIV as available in game and ending with the PzIII J as they currently have.
The Soviet aircraft for the period are accurate including the IL-2, the German line up is similarly biased as the tanks by including obsolete vehicles at the beginning of the progression, but it evens out after level 7 when the Germans get their Stukas.
The issue with the T-34 and KV-1 variants as well as potentially some of the others like the SMK or T-35 might be with balancing, since it would require an adaptation of the 88mm in some form (either a special squad or build option for the engineers) for the Germans to deal with them effectively, although the 50mm available in game should also be effective once they tune up the ballistic and damage models.
Having said all that, the corollary is that there are no “nerfs” necessary, just slight adjustment to better reflect what was historically available and you’ll find the game play somewhat more “authentic” but not necessarily “balanced”