Notice only one of the songs mentioned is from the newer stuff.
Petrucci USED to write great guitar solos. Now he shreds. Really fast. Whoop-dee-fucking-doo. Stuff like I&W and ACoS were amazing, but now DT seems content with being "a band that can play their instruments really fast."
Indeed.
I think JP's a great soloist, but a terrible shredder - Romeo shreds in almost every solo he plays; but it's always new, fitting, interesting, and memorable. Petrucci's shred sounds like a blur of pointless notes.
JP is amazing, his fretboard agility isn't seen too often. He's just boring as fuck. "Wow, look at me, I can play faster than you!" And Romeo certainly does keep it interesting in every unique solo he performs. Some say he sounds too similar to Malmsteen, and in some ways he may, though I tend to believe he's a bit heavier with much more emotive solos(though I love Malmsteen's work greatly).
And I'd like to second Gilmour for G3 (unless the other choices include EVH or Romeo).