Got some news for you. The SU-76 has
- 120 dmg until it hits vet2
- a very small firing arc
- 400 hp which makes it a 3 shot vehicle, instant engine criticals, it also has just half the armor of the stug
- inferior RoF
...while being cheaper, having more range than the stug and offering a free barrage ability to scare away the enemy.
Su-76 has one of the lowest XP values for a TD even lower than an m20 and simply vet way to fast.
In the patch by vet 2 its DPS vs Tiger is very close to that of Stug vs Comet.