On to gameplay.
What exactly would be the powers of this NKVD squad? (Ignoring for a while it would be unhistorical to say the least.)
Just an aura buff? Why? Because the other factions have that toy in the form of units? Soviets have plenty of aura buffs but as call-in from commanders.
USSR infantry isn't horrible, Cons are incredibly versatile and quite resilient. They work wonders in tandem with support units and vehicles.
T1 Isn't shit, Penals are great, snipers awesome and the clown car is a very valid build. People prefer the T-2 due to the current meta, but if people were to experiment a bit with T1 it would be more popular. As more people learn how to counter maxims, T1 will be more popular.
The Soviets aren't lacking so much as to add this unit. The only argument I see is that you'd think it be cool.
I think, that "aura buff" will be bad idea. Maybe they should be like Imperial Commissars in DoW - shot one "coward and traitor" down and grant short but efficient buff for all squads around. Maybe they could also have ability to shot one "coward and traior" for to break supression and give short time immunity for all squads around, like USF Capitan's "On me!". I think all his abilities should be connected with executions or pressing on soldiers. Hard frontline motivating, in other words. And Im not joking.
It might be "historicaly wrong" or something like that, but Relic doesn't care about history in CoH, really so, that's last point which we should think about.
USSR's stock infantry is really horrible, if you will compare them with stock infantry of other factions. Cons are worst stock infantry in game at all (if we don't talk about engineers squad, of course). Low accuracy, lowest rate of fire, (as I think) increased "recived accuracy", and no way to scale them to be effective in late. No additional weapons without doctrines, and no officiers to buff them.
Same Artillery Officier of Ostheer with his "accuracy buff" turns Ostheer infantry into monsters - they almost never miss with that and dealing huge damage. But without him - ostheer infantry is pretty weak. So, adding officier is a good way to making poor infantry more effective.
And T1 is horrible shit. It has no AT, and only specific thing it has are snipers. Clown cars dying from fausts and fast-shrecks/222s, and Penals are just "little more effective version of Cons, without AT nades, but with big explosive rack". They are "situative usefull", not like "always usefull" Obers, for example. Majority won't pick T1 not because "it's such meta right now", but because units in T2 simply way better, than in T1. And adding Commissar in T1 will make it more reliable with intresting playstyle "without supports, only with straight infantry forces". So, why not?
And most obvious - don't you think, that USSR is already feel luck of a lot type of things in compare with all other factions? USSR doesn't have static defenses (bunkers/MG positions), but all factions have. USSR doesn't have non-doctrinal AT-weapons for infantry, all other factions have. USSR doesn't have officiers, but all others have. That all makes USSR looks pity...