Uhm, that's the point. P4 is a complete package with both AT and AI capabilities, T34 is not.
And OST has even better AT gun for AT purposes (better pen, better vet ability), two respectively better tank destroyers that also happen to deal damage to infantry while having better survivability.
M4 has better AI performance than P4, self repair, smoke and it can still threaten P4 and force it away. Risking a duel with an M4 is, well, a risk. T34/76 can do none from that list, so why even bring this up?
You could also phrase it differently: You get about the same capabilities on AI as a more expensive unit, yet also okay-ish AT.
My point mentioning the SUs and Zis was, that Soviets have other (decent to very good) sources of AT. The T34 does not need to have super good AT, because it can already fulfill its role decently: flank on the attack and act as a bumper so that Axis tanks cannot rush the SU85, because they would suffer close range and rear armor hits.
And there are two points from my Sherman example: 1st price increase (as gbem suggested below) would be necessary; 2nd the Sherman still loses at long range by a decent margin. Just performing one test setup that already heavily favors one side by design does only allow limited conclusions, since at close range these tests would work out quite differently.
It could be worth testing. Leave T34/76 vulnerable as it is now, but simply increase its penetration to let's say Sherman levels, just so that P4 needs to take some hits when trading blows and think twice before doing some risky moves. That way it will still win most duels thanks to superior armour and penetration and T34 will typically need to retreat from it when without support, but it will allow SOV to punish mistakes, the bounce RNG is now a bit too favourable to Axis when retreating after overextending. Of course this should be accompanied with a rebalance of tech/build fuel cost of T4 and the T34.
The T34 is also not meant to slug it out frontally on long range. Don't get me wrong, I am not saying a T34 rework would not fix any issues, I am saying it would just create others while not addressing the core issues that Soviets have, because I do not see limited AT capability as one. Also, it would standardize yet another unit to make it almost a carbon copy of another one.
To be honest the biggest issue that the T34/76 currently has in my eyes is that it comes one minute late (compared to Ostheers especially) due to Soviets higher tech cost. Actually the P4 often comes earlier because Soviets invest 40 fuel more into LVs than Ostheer. This does not allow Soviets to play the T34 like it was supposed to be played: Amass a couple of them and push.
*EDIT: Sorry, wrong quote allocation in first version