StGs are way too strong for all of five volks and splitting the squad up is extremely inelegant. The currently proposed method makes the upgrade either a no-brainer or a waste of munis, instead of a solid strategic choice. It's just not conducive to balance.
And this is all not even considering Sturmpioneers already have a set of StGs.
I think anyone with half a brain can see that Stg44 on 2 volks is a dreadful idea. I agree, they need an upgrade which is inline with their role, not to become sturm lights.