The balance team acting real smart by making the su-76 a LV counter, but then they force it to have unreliable on the move accuracy and low damage per shot...on TOP of being a casemate...
the stug doesn't have unique playstyle, it is a cheap TD that can penetrate every single allied medium in the game, with a rapid firing rate and an ability that stuns tanks. panthers basically are panthers, most people lose them due to their own failure
I am all for reworking the SU-76 into being a TD with the option to do a kv-2 siege for artillery support, or even an ability that gives it better damage and pen for a limited time (or straight up fuel upgrade that upgrades at t4, that turns it into a zis on wheels). But wait, SOV cant spam the same unit and be strong, that would be unfair! why should those pesky commies be allowed to do what we wehr/okw players do?
The SU76's AT performance is actually fairly decent for its timing. The Puma might have a turret, but it actually has lower accuracy, even on the move despite being a much more mobile unit.
In the second paragraph, I don't understand where the disagreement is. You just described why StuG and Panther have a different playstyle: one is cheap, static, with high ROF but fragile, the other one is expensive, mobile, with low ROF but durable. You will use them differently because they work differently. Unlike both SUs, because they are functionally the same unit.
The SU76 is mostly a victim of its own faction. It's AT is not needed at the time it comes out, buffing the AT means it will become too similar to the SU85 (which basically is a ZiS on wheels already). At the same time Soviets already have two AI vehicles in T3. Without changing the infantry pacing, I'd probably still prefer StuG E like unit and completely remove the AT vehicle of T3. That would be at least unique to Soviets, whereas another AT upgrade makes it pretty much an SU85 if the upgrade is supposed to be useful.