Remember than Aimed Shot does stuff other than stop tanks turrets from functioning. It would be a buff to the StuG III, not a nerf.
OKW Puma aimed shot can target any enemy unit except buildings and has differing effects based on target.
On penetration (double penetration values of normal shot):
Turreted tank: lock turret (15 seconds)
Assault gun: stun vehicle same as Ostheer TWP (5 seconds)
Light vehicle: engine damage (anything lighter than a t70 more or less, t70 still counts as a tank)
Team weapon gunner: temporarily disables weapon (5 seconds+redeploy)
Infantry (including team weapon gunners): death crit in 0.5 radius (for comparison grenadier riflegrenade kill radius would be 0.875 on full health models). But unlike riflegrenade this will not take any penalty from green cover.
I'm failing to see the buffs. MAYBE it would be good against clumped units, so just remove been able to target infantry.
Main gun disable (5-8s) for assault guns should be fine.