The more I think about it, the more I like the idea for the panzerbuchse rifle instead of pshreck for grens. Pshreck can then be reduced to 70 mu, and given to sturmpios who are not really spammable. The reason I hear a lot of the time for the shreck on the volks being important is so that OKW can fend of light vehicles, and if anything the panzerbuchse rifle will have a higher DPS and therefore higher value vs. light vehicles.
Of course, such changes will also require a buff for the raketen, most likely a reduction in the weapon "ready-aim" time.
In terms of price, I like the idea to make the AT rifle cost 35 mu, or maybe 50, and then panzerfausts for the squad (AT package). I doubt that guards syndrome will be a problem since volks are not really good AI infantry, and don't lose too much DPS when they swap out a rifle for an AT rifle. It will be similar to the conscript AT package, except that they will have access to one slightly better rifle.
+1
I could really see the panzerbuchse rifle working well for OKW. Particularly if volks were given faust. I would suggest that perhaps sturmpios should mirror PGrens and buy two shrecks for 120+ muni however. That would help consolidate their role as AT infantry and ensure that buying the shreck upgrade is a tactical choice instead of being automatic.