Cool, except they are not. There is nothing that volkshrecks do that puppchen/puma/JP4 wouldn't do. Same for grens and MG42s and snipers. Unless what you want to do is your fav and only playstyle mr.Blobberino.
I can say as well that "demos are absolutely necessary for sov to fight late game superior axis inf without the need to spam elite infantry".
Uh, no. The puppchen/puma/JPIV do not make the existence of shreks nill. Volks are only good because of the shrek they carry; why is this shrek so valuable? Because it gives OKW a way to make up for the fact they will always have less vehicles than the enemy will. Decent shrek play is the hallmark of any good OKW player.
Grens need the LMG42 because Ostheer has no elite infantry to compare to Soviet elite infantry. If grens lacked the LMG42 they wouldn't be able to stay on the field and remain useful after shocks and guards hit the field. The LMG42 is very fundamental to the way the infantry dynamic of Ostheer works.
So concluding from those 2 facts; the 2 most basic Axis infantry would cease to be useful without the LMG42 and Shrek package thus the removal of said upgrades would be massive blow to each faction were as Soviets would NOT be worse off if the demo charge was limited to a timer based one like the Para (which is useful) or just limited to being put on buildings and bridges.
Soviets now have a good MG that can do AoE suppression, both Guards and Shocks are useful, the M5 rips infantry apart. Soviets have absolutely 0 issues with Axis infantry late game without the demo charge.
Again: The democharge punishes smart players who flank and spread squads out around the map to establish map control. The demo charge encourages blobbing because it forces a player to put all there important infantry with 1 sweeper squad.