The M-60, as well as the German machine guns, were not innovative. The most innovative thing about the German machine guns was the rate of fire, and given that it forced you to swap barrels, it was as much a hindrance as it was innovative. The M-60 is not that great a weapon, and it never has been. Like the M-16, it was originally a problematic weapon that after much refinement became a decent weapon.
The most innovative German automatic, with the longest lasting effects, was probably their assault rifle, which was the first. There were submachine guns around before the German examples, their most innovative quality was their weight, and lower recoil.
The Dillon is not really innovative, it is more of a refinement. The various GE electric powered rotary cannons were around long before Dillon, with all due respect to Mike Dillon.