I think that the SU-100 and SU-122 should be added, the SU-122 under artillery, and SU-100 as an SU-85 upgrade.
su-122 would have paper armor and meant to be a fire support unit...not very good aganist tanks.
maybe the SU-100 could be an upgrade to the SU-85...cause in reality thats all it was...an Su85 with a 100mm cannon.
the KV1 could also be added..but if the Kv2 is in i guess its not needed.
in addition, the ML20 is not a 120mm cannon, but a 152mm cannon. The same cannon as fitted into the ISU 152.
also could maybe the T35 be put in? the huge fortress? lol