So that should at least stun enemy infantry and therefore block them form using the snare. Currently i don;t see any point of using it. Sturmtiger bases on long range shots far from line of sight and this ability is short range, small grenade that do shitty damage that has 0 impact on a battle.
I would trade for something else - for example flare (like soviet sniper) but i guess again for some that would be opieOP.
I think it's fine, it's only 20 munitions and causes enough damage on a good hit to force off a squad or crew weapon without having to waste the rocket or before reloading it. It might even wipe squads that are clumped together. 35 range is enough to use it through sight blockers. It's good for self defense when being chased by AT infantry after having used the rocket now that it can be activated on the move.
It could get better mid range AOE to put it in line with regular grenades but I don't think it's needed.
The vet 1 ability of the ST could fire bouncing mines around the vehicles it would work both for balance and for historic reasons.
I doubt that would be possible due to lack of animations. The Sturmtiger's mine launcher was a single turreted mounted launcher as opposed those other vehicles' multiple one-off all around mine discharger units I imagine you are talking about anyways.