While I'm getting your concept, I think it'll need a bit more work to get it working just right (which, as stated by the others for the potential for a high degree of similarities between REs and Rifles after that, is a dire priority). A Riflemen nerf of some kind would also probably be necessary as well to highlight using REs to spot and hold ground while the Rifles get in position to attack to ensure we don't just buff the USF's starting unit's initial performance a bit and then building more gets ignored, especially since REs won't be as dirt cheap to encourage getting some for more sight and capping.
We must buff USF until all their core infantry shoot M203 grenades out their ass at vet 3, this will help them scale better along with volksgrenadiers.
Then, just then they might be a viable lategame faction. But only if all Sherman variants also receive a Tomahawk attachment to one shot any axis vehicles while playing "Freedom isn't free" over the ingame OST to deafen the axis players into quitting the game.
Your proposal sucks.
It's entirely without bald eagles.