Rifles have enough. They already have carbines rather than bolt action rifles.
Rifles definitely don't have enough weapon slots. There is a reason why we rarely see the bazooka upgrade. Not only because it has less effectiveness than a panzershreck but it takes up HALF the slots on a rifle, and reducing the rifle's effectiveness against infantry. For a squad to be effective AT they need at LEAST 2 bazookas which takes up all the slots so the rifle will be lackluster against infantry. Having more weapon slots let's the bazooka be used more often, also allowing more varying strategies from US players.
And what about the other 'terminator' squads? Obersoldaten, Jaeger light infantry, panzerfusiliers, falls? Rifles need BARs or lmgs to compete late game with them. Take the panzerfusilier for example... They have a 90 muni upgrade which gives them 3 G43s, US needs 120 muni to upgrade 2 BARs. And panzerfusiliers can still pick up weapons off the ground. How is this fair that they are straight up better than the only mainline infantry US has?
And this wouldn't be OP lol, if you let the US player get away with spending 180 muni on 1 rifle squad then you screwed up somewhere. But imo the browning m1919 should be nerfed to 2 weapon slots. Getting 2 on one squad is a bit excessive.