Like all rolling stones lists, this has major problems. Some of these people were amazing musicians, songwriters, entertainers, but not "great singers." On the other hand, some of them were truly great singers. It was fun trying to figure them out though.
I agree completely. I was amazed to see some of the people on the list, great musicians as they may be. They'd make the top spots on "greatest musicians and/or songwriters" with flying colours, but as singers....hmm.