This is not a technical issue just some squad balance suggestions.
Restrict US sniper class to recon squad
A 3-9x scoped rifle with AP rounds is an extremely powerful weapons system to have in all standard rifle squads, also historically inaccurate. Move sniper to recon squads and replace in assault squads with a designated marksman equipped with armor, a helmet (maybe camouflaged?), and a M16-a2 equipped with a 4x scope.
Introduce HAT kits
The US definitely needs a heavy anti-tank weapon and this role would also give an excuse to add a soviet class equipped with a RPG-7. Available in a new rank-locked squad for balancing. Good opportunity to add AT4s and either recoilless rifles or M47 Dragons.
Just some ideas!