I think the problem is that the t34 was made throughout the war, so it's armor was comparitively weak by 1945, but nonetheless, the sloped armor always helped.
Panthers were developed as a response to the t34, but better due to the heavier armor. Nonetheless, the t34 could still destroy the panther with the 76.2 with luck.
The 85mm gun was designed to kill tigers, so the t34 would have been on an equal footing overall to the panther except in crew training.
You're suggestion doesn't really fit into company of heroes since panthers could just have easily (if not more easily) destroyed shermans, what with the ronson effect etc)
making the t34 poorly armored just isn't accurate for coh: the t34 faired excellently against the 37, 50 and 75mm guns, whereas a Sherman would burst into flames at the slightest opportunity...