Volks should choose between MP44 + incendiary nade upgrade that requires Mech HQ tech, or Shrek + faust upgrade that requires BHQ.
Cons also could use some sort love lategame, as well as T34. (Off topic.)
And then you'd have twice as many volks, half with shrecks, half with ai upgrades.
This is exactly why volks won't be getting any other upgrade as long as they can have shrecks.
Also, 5 other dedicated AI squads are good counter argument why they should never get it.
As cancerous as shrecks are on them, they aren't going to change that.