You are taking only okw to the equation, while usf outfields ostheer too. It doesnt matter too much if you outfield the enemy if everyone rushes 50 cals. The only problem I find with USF vs OKW matchup is the disparity between the sturmpioneers and the enemy squads, which is not that big compared to the one with soviets and combat engineers. All other factions have to pay for tech but they dont get a squad with it, hence, its free. If officers stop being free probably sturmpioneers should get some nerfs too.
Relic didn't removed them when they refreshed USF tech, can't see any new opportunity to do it now. You also have to take in account smoke nade that have been given to officers to mitigate riflesquad powerness, having smoke nade only on RE or units you need to purchase is quite a huge additional side nerf.
Supervision becomes also quite useless if you need to purchase the captain to use it.
Y don't see USF outfielding Ostheer when Gren cost 40mp less than rifles, usual Ostheer strat is going 1xHmG + 4xGren early game, vs 3xRM + 1 officer and then .50. Now, removing the free officer will upset even more the OKW's manpower advantage they get early game over USF.
I've always been in favor of removing free officer but that's should be part of a biggest design overall that just "let's remove them and see"