I have the impression people are looking for a unit or improvement that would win for them the game.
Volk aren't mean to be strong ai, they are mean to be cheap meat shield. And you use them to cover your elite infantry. early Sturm, mid whatever doctrinal, late obers. Now many people simply forget to put that elite unit behind them, they just spam volks until rifles/IS are well fed and vet3 and your folks just trash.
Lets also not forget that in addition you have very strong anti infantry vehicles to help you.
Unfortunately, Volks are bad at everything, including being meatshields. Even at vet5 they are about as durable as a 5 man vet 0 infantry section. Your logic is valid, but I have an impression that OKW was not designed this way by Relic.
I'd really just swap Obers and Stuka zu Fuss in their respective tiers. That way they come earlier and are more available overall, resulting in less Volks spam and Mech HQ being more viable. Also, tweak volks vet so they have better RA.