That's just my opinion but
Volksgrenadiers
260/26
One man added (now a 6 men squad from the start)
STG 44 upgrade removed
Veterancy 4 bonus (sight range) replaced with -15% RA bonus
Veterancy 5 bonus (passive healing) replaced with -15% weapon cooldown
Sandbags replaced with Conscripts sandbags wall
Now they can pick up dropped weapons [1 slot] (obviously since there's no stg44)
Sturmpioneers
300/25
Now starts as a 5 men mp40 squad (with Assault Grenadiers MP40)
After one truck has been fully set up they can upgrade
>Assault(or whatever) upgrade 60/80 munitions
4 Panzergrens STG (more mid range oriented, previously this is what Sturm stg were before being tweaked to a more close range profile) and an unremovable minesweeper always carried by a model
>Panzerjäger(or whatever) upgrade that is the current one
>Minesweeper upgrade (mutually exclusive with Assault upgrade of course but not with Panzerjäger upgrade)
how about:
Volksgrenadiers
260/26
5 man still
STG 44 upgrade remains
gets a third one(STG) with panzer authorization
Veterancy 4 bonus (sight range) no change
Veterancy 5 bonus (passive healing) no change
Sandbags kept as is
Now they can pick up dropped weapons [1 slot] even with 3 stgs (because you really can`t rely on picking up enemy weapons, but if you manage you have a killer volks now)and fits with faction resource starvation/salvage
which i think would be minimal changes but would give volks a edge
Sturmpioneers
300/30
Now starts as a 4 men Gewehr 43 squad (with tweaked stats but more a mid range profile but usable close range)
After one truck has been fully set up they can upgrade
>Assault(or whatever) upgrade 50/60 munitions
3 STG (more close-mid range oriented)
>Panzerschreck 70 mun(same as now)
>Minesweeper upgrade 30 mun(same as now)
>all upgrades can be made(nothing mutually exclusive with one another)
With this i think they would not have to solely rely on ambushes on early game or retreat paths wipes, and a full upgrade would leave them with the with 2 STGs,Panzerschreck, and minesweeper or 3 STGs and minesweeper as they have with current patch.
Or instead of Gewehr 43 just adjust the initial STGs which would also be fine.