su76 should be a mobile light/medium vehicle barrage tank. The reason Soviets have 2 TDs (although su76 is not a TD in it's regard) is the fact that soviets have piss poor infantry AT. Brits have piats which, USF has zooks, Axis have the best panzershrecks. Soviets have "Fast" firing high caliber rifles that can easily deal with light vehicles but rely on low range satchel to kill tanks. SU76 is there as a cheaper alternative to SU-85 to complement ZiS builds. On first glance, you'd think it's got no place but it does. It should be a tank you get to push off mediums for less fuel, giving you time to bring out katyusha or t34-76.
It's got 400hp, 120 dmg (40 less than regular tanks), 160-180 penetration -> enough for mediums like OST P4 (hardly for OKW P4).
I think what would make it viable more is any buff to it's barrage. Whether CD or cost. It's role would then be to fill in the gaps between SU-85 and ZiS. More mobile, easier to escape vs infantry and better repositioning to deal with blobs with barrage.
I've heard somebody say that SU76 used to be OP. I haven't played the game when it came out so I don't know but that's how I see the SU76.
SU-85 should remain the same.
SU-76 should be a response unit. Has AT capabilities up to mediums. Has AI capabilities in a sense of barrage to support infantry.
ZiS is ... well, ZiS. Less mobile SU-76 that costs no fuel and has better penetration.
I think SU-76 exists in order to fill in that gap. If you go for penals/snipers, you can go to T3, skipping maxims and ZiS and yet not losing the early AT capabilities.
I think the unit is fine. It reinforces that Soviet versatility notion.
