LMG's to keep up with the Americans, even when BARs were fielded. MG 42's were so strong they didn't really need babysat, anything in-front of them was prey except Rangers or Airborne. Now Grens might not need LMG's to keep up with Conscripts, but they certainly need them to keep up with USF.
Back into vCoh, Rifles were more or less the same vs volks. But volks had a SMG upgrade making them deadly at close range and BARs was a universal upgrade for rifles.
To me, it would make more sense to give LMG to grenadiers and not volks. Volks could have a SMG upgrade from T2 as in vcoh
Unlike Romeo, I think a Blob should be treated, whatever unit you're blobbing.
A blob of Rear Echelon should receive the same penalty than a LMG blob. But I feel it is really difficult to put in place this kind of modification. Because its need a strong definition of what is a blob, which spacing between units, what if the blob is composed of 4 different units from 4 different players, what about bottleneck and shock points where you need to concentrate your force to attack etc...
So dealing with the concept of blob itself is probably not the easier way to tone down it.
And yes, it is probably far easier to deal with what make people blob a lot: Powerful LMG and shreck.