I'm a big DT fan, but not really a prog guy otherwise, and I'll admit that I've never heard of most of the others on the list. But after sampling them, all those other players just sounded like they were doing very random technical noodling to me. I basically get
nothing musical out of what they are playing.
Now I'm not saying they aren't talented - believe me, I think they certainly are - but at the end of the day, all the great playing skills in the world won't get you more listeners other than a very limited hardcore fan base if your music basically amounts to what sounds like atonal, free jazz type of music. In fact, a lot of it reminded me of some of Frank Zappa's more way out stuff that I admire for it's virtuosity, but I just don't really
get and thus don't like to listen to.
I realize I've kind of stepped outside the purposes of the list with these ideas, but that is precisely the point - it takes more than just skills to be a great guitarist. In fact, I would say it's technical guitar skills combined with song writing capabilities, stage presence, other abilities (can sing, etc).
Personally, I would pick John as #1 because he is all of those things. His solo material from the G3 DVD from the mid 2000's is what drew me to him in the first place, as well as to Dream Theater afterward. It's also because plays very memorable melodies besides all the technical wizardry he is capable of. In fact, I think some of John's best playing is the slower melodic passages that he does like the solo for "Repentance". And I really think John upped his playing for DoT as well.
Just my 2 cents. So go ahead, you can throw rocks at me now
And congrats to JP regardless!