Because it's music/art, and everyone's taste is a little different, I do think you can split this into several different categories.
There is a difference between being able to play incredibly technically and fast, injecting massive amounts of soul, the best song writers, the most unique, different, and innovative techniques, etc., etc.
Frank Zappa said that Steve Vai was the best guitarist he's ever heard. How they met was that Vai took one of Zappa's wild, free wheeling jams, wrote it all down note-for-note in musical notation, and mailed it to him. Before he had heard a single riff from Vai's guitar he knew that this was an incredibly gifted person, and when he asked him to come play with him he said he was as blown away as he had hoped when he saw his own jam in musical notation that he could have never transcribed.