OSt is build around crutch MG42 because of glass-cannon gren. My solution: Switch MG42 to OKW (but reduce supression to MG34 level and change price to MG34-level, but give slight increase too damage), give OST MG34 with old MG42 stats/price except nerf supression but therefore give Gren timed supression ability at Vet1 (like Obers but without limit to 1 targeted squad, Medikits only for Pioneers). This would also have the bonus of faction uniqueness + historical accuracy (Ending ahistorical nuisances like late game German army(OKW) using the older MG34, the MG34 being cheaper than the mass-produced/more economical MG42 )
Give them basic repair ability(like doctrinal cons) and for vet one the ability to reinforce next to all friendly vehicles like they were halftracks (copy the script for pathfinder-beacons/paras minus the airdrop animation). Fits their historic role (mechanized inf) + unique feature and balance between utility and (stat) buff (indirect buff to durability).
It's amazing how you can regularly still get matched with players that still can't adapt to the overdue nerfs on the Comet and than fail hard by relying on it as a "nail in the coffin"/shock tank like it could be used in good hands once. I mean, man, that patch came in fucking December if remember correctly. Disclaimer: This is of course only ancedotly.
Switch Penals and Guards Role. Like they should have a long time ago. Penal can even get Flamethrower back. Soviet still keeps "Elite" Inf and light-AT option in T1 but is is also better for historical acurracy(using irregulars and "suicide-squads" as elite inf for soviet faction - 1st class nazi propaganda you got going there relic)
Remove Sherman 105 from Doctrine (Replace with M8) and put into T4 but give old Stats back + health buff = Meatshield-ish tank with crap AT, just like KV1.