I agree that these are pioneers but I wouldn't say crews they operated as a group. IMHO a crew is a collective of individuals who on they own hold it down but in a group of like skilled brothers, put the game on choke. The groups you mentioned, function strictly as a group and not a crew. The Juice Crew is the ultimate Crew. Each one on their own held it down on their own but , as a group, they could not be fucked with. CCold Crush, F5, T3 & Run, were all nice as a group, but one on one, the majority of the members were not as nice as the group over all. whereas in a crew, each hold his own individually and as part of a crew, keeps shit on lock. Perfect example is the Symphony by Marley Marl. Each member of the Juice Crew, had shit on lock (Shante, Shan, Biz, BDP, Kool, etc) and each was nice on their own.