Sandbags didn't have any effect vs panzerfausts or other shells, what they did was stress even further the sherman transmission, and was being constantly banned by High Command Regulations
For a long time, Urban Defense Tactics of the SU faction has had that one black sheep, called Armored Vehicle Detection. I say make it a true Urban Commander and replace it with Conscript PPSH's (or in a more extreme measure, shock troops or partisans with ppshs).
Forward Observation Post has a smoke ability, but when launched it uses phosphorous. My only remark is that this isn't properly identified, which might be a but of a shame, since in coh2 there's a big difference betweeen smoke screen and phosphorous smoke shower.
Does Lend-Lease look not so lend lease to anyone else?
I'd say replace the Dhsk with the .50cal Browning (and adjust price accordingly);
Replace conscript repair with Radio Intercept or Spy Network (to symbolize Allied Intel Intercept being provided to the Soviet Union)
Replace the weapons on the Assault Half-Track with either 4xPPSH-41s or 4xSVT 40s and 2xBazookas (Which the Soviets received as early as 1942 from the Americans)