This thing needs to be fixed, its about time. It can be used in 2 commanders Soviet Defensive Tactics and Urban Defense Tactics both of them can be somewhat underwhelming, or at least sub par compared to other soviet commanders. Fixing this unit supposes one less nail in the coffin for this two well known commanders, improving the soviet roster adding choice and variety.
I can come up with 3 solutions:
Buf it or add already tested features like a soviet raketenwerfer or similar (in my opinion the most boring of the solutions, and maybe not enough to make the commanders worth it)
Redesign the unit, it could be redesign to feet other roles like a poor's man static t70 AI unit.
Add special useful abilities. In real life the thing was produced until 1945 it used the following munitions:
Armor-piercing
Fragmentation
Canister
Smoke
Any of those are good excuses for abilities for the unit, what about one ammo expensive AI shot, or smoke rounds for a period of time like mg ap rounds/incendiary. it was reported to be able to pen the panther sides, what about special bonus against rear armour or deployable from buildings like partisans.
All of those are just ideas, some of them sound crazy but if you think twice, those commanders are not particularly good, and anything can be balanced with pop cap, cost, man power bleed, ammo ...