I'm not entirely sure that just sandbags is enough to tone them down. Regardless of cover volks are extremely cost effecient, especially with STGs. Don't get me wrong, sand bags is a start, but I don't think it would be enough
There is a weird balance between volks, penals, and infantry sections. You nerf one you have to nerf all of them. Usf infantry could have its stats shuffled around to allow them to compete. Everyone is going for cav rifles, paras, rangers, or assault engineers which is far more interesting than rifle spam.