The thing about EVH is that he invented a new way to play the guitar. He was a trained concert pianist (no jokes here...) and the intervals available to the piano are not traditionally achievable on the guitar. Thus, he made up his own way to get the melodies he heard in his head. Edward is one of my top three guitarists in Rock for that reason.
Who are the others, one might ask?
OK, to qualify my opinion (that and $3.50 will get you a cuppa joe), I have played guitar in bands since 1961, have been active in music since 1957 - the golden age of RNR.
The first and foremost influence on modern guitar, in the Rock'N'Roll genre is and was certainly Papa Chuck - Berry that is. He was self taught, as all innovators are, and loved the horn arrangements in big band records. His ears told him that to get that same thang on the guitar, he had to 'double-stop', which is a violin technique (listen to the startup of the slow string thing in "The Straight Story"). That was a new technique in 1955-56, and he used it to great advantage, along with Johnny (insert last name - my brain is as blank as a fart)'s brilliant train style piano playing. MOST rock guitarists pull their armament from a combination of Chuck and the older Delta Bluesmen. Including most certainly Senor Clapton and his ilk. NOT to take anything away from Eric, but he is a copyist, not an Innovator. And I know Chuck is a bum today, but he steadfastly trod the Glory Road.
The greatest guitarist between Chuck and Edward was - yup - Jimi Hendrix. Jimi was the second invention of Rock Guitar, in that he played the thing unlike any before him. He was also self-taught, though he had great road training with The Isley Brothers and such. Hendrix took the power trio to its apex, with the necessity of having to cover rhythm and lead parts at the same time. His melodic chording, or chording lead style, was unique, and has been many other guitarists' ticket, i.e: Robin Trower and SRV. they are both great technical guitarists, but not Innovators.
IMHO, ALL other guitarists are distillations of these three huge cornerposts of Rock Guitar. Yes, many had other influences, like Beck, McLaughlin, Vai, etc,. who pulled from the Jazz lexicon, but they were all derivative guitar stylists, not originals.
It remains to be seen who will be Guitar God #4.
OK, fun stuff. Discuss amongst yourselves... There will be a test.