Mastery, passion, intelligence, creative genius, humility, and modesty...Mahavishnu John McLaughlin had it all. With Miles and then with MO...transcendent.
But maybe you don't count him as "Rock".
IMO Hendrix was the greatest in Rock history in that case. Beck, Page, Clapton, FZ (and Dweezil), SRV, EVH, Larry Carleton, you name it...none contributed as much to the development of "Rock" as Jimi did in his too short life on the scene.