I think the T-34/85 and the M4A3(76)W should both be lightly perked. They both have some very good traits.
Cross country speed: t-34
rate of fire: m4
Armor penetration: M4= t-34 w/ap < t-34 w/hvap
armor: with its invincible turret I score this one for the m4
Miscellaneous wins for m4: 5 cal pintle, default color scheme, depression angle on main gun
Miscellaneous wins for t-34: haul armor, difficult to kill with IL2 , HE damage, turret speed
In all I think the M4 and T-34/85 as modeled are comparably deadly and survivable and both warent the light perk price that is currently on the T-34/85.