That's why they needed the M
The T34 was designed as the final of a series of shellproof tanks. In order to make it as hard to kill as possible, it was made as compact as possible, and the turret was particulary small. That made for a smaller target, and the less area you have to cover the thicker the steel for the same weight. Since it was to be a breakthrough tank (a fast Matilda with a real gun, if you like) the fact that the cramped, cupola less turret made it difficult for the two man in the turret to fight other tanks properly was accepted. The main tank was, after all, going to be the lighter, faster, T50 with a dedicated 45mm AT gun in a three man turret with a commanders cupola. When the T50 proved to be unreliable, it was decided to stndartize on a new, better T34 with all the advanced features of the T50. And since the initial trop trials of the T34 had found it unreliable and difficult to drive, the new model w given a revised engine, mounted longitudaly with much better space for maintainance work, and critically a new transmission with a reduction box that gave it twic the gears and was expected to be much easier to drive.
Now the T34 suffered hugely from reliability issues, so the M, if it worked as advertise would be a big bonus. But I'll stress again that if the Russians used rudimentary tank tactics in 41, 42, and 43 that was not only for lack of training, but because in a tank without a dedicated gunner and poor visibility the gunner/commander had far less options and time to think than in a tank with a proper turret.
So better tank, beter performance on the field, much stepper (upwards) learning curve for tank commanders, much better kill ratios!
And it would be doable if they had droped the T50 and concentrated on getting the T34 right earlier. Note that the troops were so unsatisfied with the T34 before the war that there were requests for it's production to be stooped in favour of the BT7M until the T34M could be produced.
After Barbarrossa there was such a huge need for tanks that it was to late and the soviets were going to fight with the T34 for the rest of the war.