Its because of the received accuracy of rifles as well as their range limits that makes it hard to keep them in the game. That coupled with the 28mp reinforcement makes the bleed rly hard to keep more than 3 alive in a game at all times.
" flamers/m1919's" are also a doctrinal item and require you to lock yourself into a commander before the game even kicks off.
Rifles are good at all ranges and are cost effective to boot, are you sure you're not talking about sturm pios here?
Doctrine choice is hardly an issue, short range map you can basically do what you want as BAR/flamer spam will kill everything. Even on a map like minsk you have choices, 50.cals, BAR pathfinders, m1919 rifles and paras are all good and they're hardly "locking" your doctrine options when USF don't have to rely on doctrinal call ins at all.
The real issue is the lack of elite infantry USF gets excluding the paras making an OKW player who spams Obers deadly as the MP drain on the USF player will be horribly hard to keep up.
Rifles with m1919's will out trade obers, or any other OKW infantry due to free supression. If you think 28mp is expensive try dealing with 50mp per model and a much longer reinforce time.