Oh, man, I almost started a thread asking the exact same question!
I'm a connoisseur Old Skool 1970s prog-rock: Yes, King Crimson, Gentle Giant, the Canturbury Scene, etc.
But a lot of contemporary prog leaves me underwhelmed, because it sounds like it absorbed a bit too much of the 1980s hair-metal pyrotechnics, and so it winds up sounding like a Slayer tune with some odd meters thrown in.
I can't stand Dream Theater.
I think Tool has some killer grooves but their tunes never go anyplace, and so their relentless monolithicness just gives me a headache after a while.
Even the coolest modern prog bands that I've managed to stumble across -- District 97, Birds And Buildings, Thank You Scientist, as well as stalwarts like Porcupine Tree -- all seem to have a substantial part of their musical vocabulary derived from heavy metal, be it the crunchy Dual Rectumfier guitar timbres, or the pile-driver headbanging unison riffs. In small doses that can be kinda cool, but it quickly grows tiresome to my ear.
So I would love to hear (in some hypothetical idealized world) what prog-rock would sound like if the whole guitar shredder thing had never happened. Anyone know of any modern prog bands that simply ignored that whole aspect of music history?