I've been a guitarist for over 20 years and although EVH's name has been I've been aware of for a long time I never quite came to appreciate how fantastic he was until quite recently, and that was when someone linked something for guitarists from famous bands who were also excellent session musicians and I came to appreciate how completely over the top for melody, technique and expression his few bars of a guitar solo in Michael Jackson's Beat It. Coming up with a guitar solo of such quality is near enough impossible at the best of times, but writing one for someone else's music is even more difficult!
In terms of influence and ability, he took the instrument on like Hendrix did before him and he really shaped the decade of guitar playing (and beyond) he'll be missed for sure.
RIP Eddie.