This is a concept that I've thought about for a while, but was reminded of it last night while watching an AC/DC tribute band.
First generation electric guitarists I call level 1 - guys like Chuck Berry, Les Paul I suppose - don't really know much of them.
Then came Jimi Hendrix - he took playing up to level 2. Others developed that, and guys like Page, Blackmore, Brian May, Alex Lifeson I'd call level 2+, with a bit of evolution after the Jimi revolution.
Level 3 came with Eddie Van Halen. As for level 2, others developed and improved, Satch, Vai being two that spring to mind at 3+
Yngwie took playing to Level 4, and guys like Vinnie Moore, JP and Paul Gilbert came in at level 4+
No-one has reached level 5 yet.
Does this work for anyone else? I'm sure there'll be differing opinions, and it's certainly not a statement that anyone playing at level 4 is better than those at level 3 etc. But for me, the real gamechangers in electric guitar playing were Hendrix, then EVH, then Yngwie, and that's where we're at right now!