Even if StGs could drop, who would ever waste a weapon slot on them? I totally understand the part where the StG upgrade comes fast and can be upgraded out of territory. However, I don't think that BARs making Volks completely obsolete and forcing LMG Obers is a good design. I'm not calling for a big buff, either the StG upgrade doesn't take up both slots so Volks can pick up dropped weapons, or rework their veterancy bonuses a little.
If Volks could already stand up to double BAR riflemen, how would USF be able to handle Obers on top of that?
I'm not in favor of the way USF/UKF are designed in terms of weapon upgrades, but as long as neither faction has elite non-doctrinal infantry available to them, their basic infantry kinda has to out-perform axis basic infantry when fully upgraded so they don't get rolled when axis elites hit the field.