Goal here is to fill in a perceived gap in the faction: if Conscripts are only meant for utility and thus do not get weapons, and you do not go for Shocks or Guards, then all they have to support are Penals or Maxims. Conscripts and Penals alike struggle against Gren LMG 42's and Volk StG's, and the Maxim is a weird one because the implication is that Maxims should be used in larger numbers as a frontline unit which has been heavily discouraged by Relic (the dreaded Maxim spam).
It is this shortcoming that leaves the Soviets banking on the T-70 as a make-it-or-break-it unit mid-game, in fact you could say that the T-70 is Soviet mid-game. If that is to ever change, and Conscripts are conceptually prohibited from having their own weapon upgrade, then Soviets will need something else to work with.
A further conceptual fault with the Soviet Faction is that of all 5 factions, they ironically have one of the lowest numbers of SMG's or units with SMG's. This actually was not an issue in the campaign, which granted you SMG Conscripts (often free iirc) on most levels. So I would like to see that rectified.
That is why I believe Soviets would be well served by a new unit. This unit could be given PPSh's that are slightly weaker than Conscript PPSh's, so that they do not make Assault Grenadiers irrelevant. Maybe at T4 they could be given Conscript PPSh's or even Shock Troop PPSh's so they stay relevant into the late game.
Live concept art courtesy of Cheat Mod.