Oh man, but why stop at 2? I would also accept the T34/85 buildable as stock from T4 (come on Relic, with Panthers and Stugs everywhere would it really break the game that much?) and then the T34/76 could be completely relegated to call-ins. But how to make a t34/76 callin appealing? EZ : Triple callin @ 11CPs, 600/200, 25 pop, no tech requirements. 
Okay, that might be over the top, but Soviet mediums need SOMETHING to stay in the fight against the German beasts, and in the original design it was supposed to be sheer numbers. Okay, but Relic just can't seem to commit to the idea of giving at least some leg up to Soviet nondoctrinal tanks. Meanwhile Germans get Panthers, Jagdpanzers and Kingtigers but for some reason Soviets don't get any of that except doctrinally and they still cannot get even cheap, timing-appropriate, spammable medium tank? Why is that? In the current meta, especially team games, an axis infantryman can't sneeze without four Panzerschrecks dropping out of his backpack, and literally anything Axis heavier than a halftrack will chase a single t34 off the field.
I've never once in my life seen a T34/76 and said "crap" (well maybe during their brief time as the rammobile). Make them "zerglings" as Adviser said, and they would at least be an unpleasant surprise for the Axis when two of them burst from the fog of war (and then proceed to miss or bounce off everything and anything
).
When I see a team mate get a T34 I go- "ah crap I have to do the heavy lifting here". I remember the tank rush meta where t34s would roll out en masse- that was put a stop to pretty quick.
If T34s had a it more AI they'd be at least useful as a bullet sponge/Inf counter. Right now they are only the bullet sponge part of that sentence.
You write well in English for a Serb hey.