SU-85 was a stop-gap measure to get an 85mm gun onto something to have something with higher penetration than all the 76mm gun armed tanks, so it was most certainly decently numerous late '43.
Of course the Soviets used conscripts, but the Germans did too and the quality of German troops was noticed to be dropping markedly as the fighting in Russia continued, yet they get grenadiers whilst the Soviets, whose infantry was also becoming pretty good, get conscripts.
SU-100 didn't exist until late '44.
OKW is easily a 1945 faction. For a start, all that nightfighting equipment they get (often non-doctrinally) didn't appear until after the Bulge. That alone brings them up to 1945.
One doctrinal upgrade a 1945 army does not make. And while the SU-85 was numerous in 43' it was being phased out into 44 due to the development of the T34/85, IS2 and ISU152.
And Soviets get conscripts because making guards or shocks your basic unit would be a tad silly, but conscripts are really not that bad versus Ostheer, and when spammed can be quite punishing to the enemy.
If we wanted to be realistic, Oustruppen would be Ostheers main infantry unit, not Grens. But I doubt you think that's a great idea.
But alas, Relic was at least smart enough to not try and go hyper realistic with this game. But the inclusion of the SU-100 as a doctrinal unit would be cool at least, instead of Relic making new Soviet commanders with 42 era shit.
The inclusion of the SU-122 would be interesting as well, give Soviets a nice armored assault gun like the StuG Ausf E with a bigger gun and better armor for breaking up OKW blobs.