What would be the point of getting Volks if they didn't have an AI upgrade? Since they are extremely crap at fighting enemy infantry and elite infantry?
If your going to take the shrek away you need to give the Volk squad something in return. And you know that received accuracy stuff everyone hated on Volks? Sturms still have that.
I don't think an AI upgrade is necessary. They'd be like better scaling Conscripts.
They'd need support to fight elite infantry just like every other basic inf squad. The difference is that OKW has non-doctrinal elite inf unlike Allies.
Received accuracy was a problem on Volks, yes. I don't think that it would be a problem on Sturms. They're more vulnerable to explosives and you had to retreat them once they have 2 men left - otherwise they might drop their shrecks.
It's better to give shreks to a squad that you actually have to micro because it's more expensive and easier to lose if just yolorushed into tanks.