It has roughly the same durability as the Puma but no turret nor escape smoke it doesn't have the capability to perform with lowered pen. If the player vets up and maintains one of the squishiest vehicles in the game they should certainly be rewarded well shouldn't they? Mobility is a necessity for this unit. It's all she's got. Losing human crush is a no brainer but so what if it's more mobile than a Panther when vetted? Should getting a PA there just immediately make vetted su76s explode?
If you want to compare the Puma with Su-76 you ahve to kill in mind how bad Puma is at max range:
Puma
Far accuracy(50) 0.25 Penetration 80
Su-76
Far accuracy(60) 0.375 Penetration 160.
That is more than x150% better accuracy and x200% better penetration at max range.
The unit is safe by staying at distance. It does need to faster than all ostheer tanks when it outranges them and when the barrage outranges Paks.
How are one supposed to counter a cheap unit that can barrage better than a mortar from ranges up to close to 90 that is faster than all vehicles?