yes the T-34-85 is a very good tank... the problem is without the T-34-85 youre left with a mediocre tank thats clearly not as efficient as an M4 or a P4 as your medium line tank... in fact its the faction with the least efficient lategame mainline tank... the P4/M4A3/P4J all outclass the T-34 while the brits get the option to use the comet which is a top tier premium tank...
Oh please. The T34 is already VERY efficient. It comes early and is effective against infantry and lighter vehicles. I would hesistate to say the Panzer IV has better anti-infantry than the T34; I don't know the exact stats but they seem similar enough. What is true is that it is mediocre in the late game because T34's AT sucks. Unfortunately, you are misinterpreting the role of the tank. The T34 is not a generalist like the Cromwell and the Panzer IV. The closest counterpart of the T34 is probably the Ostwind. Great against infantry and light vehicles, can occasionally tackle medium vehicles. If I'm correct the T34 is cheaper than the Ostwind although it is worse at anti infantry and better at anti tank. The T34 is not meant to duel mediums. It's meant to bully infantry and light tanks. All in all, the T34 is a great tank. But it might not be the tank that the Soviet faction needs, and that isn't a problem with the T34 but rather the Soviet faction as a whole. Simply buffing the T34 can't fix that because you'd be given it a new role as a generalist medium tank, which is not something the Soviet faction currently has non-doctrinally and could have many unforeseen consequences. Maybe you are correct that the T34 needs a role change, but it goes far beyond the unit itself and meddles with the whole design of the faction.
Also, fun fact: while the T34 had on paper had 90mm of armor, since it was only 45 mm thick, shells fired by bigger guns like the 7.5 cm gun on the Panzer IV easily overmatched the armor plate, lowering the effective thickness of the tank's armor. Because the Panzer IV's armor plate was 80mm thick, it was more sturdy than the thin 45mm plate in T34s, which was much less sturdy and only produced the predicted 90mm effective armor against smaller caliber guns. Against a larger 7.5 cm shell the 45 mm of armor simply can't absorb the energy of the kinetic impact and folds in on itself. This usually results in MASSIVE holes much larger than the usual hole produced from a penetrating shot.