Momentum can mean a couple of different things. In the course of an extended piece, it's natural to have quieter moments in between heavier/faster parts. You have to have contrast; you can't just go full speed the whole way through. I agree that that gets tedious. But if the song is a journey, you want to feel like you're moving the whole time. There's a way to have some contrast or take a breather without literally stopping everything. With "Illumination Theory", everything literally just stops. I guess I'm more a fan of movements "flowing" into each other, rather than the music completely stopping, then starting up again.
I think that's one of those things where trying to embrace the flow would be a little bit futile, though. If you want to write a song with a soft, soothing middle section, you're going to have to bring everything to a full stop - better to be brave, and bold, and daring, and have the band
actually put their instruments down than to sort of keep it humming under. Illumination Theory is more of a statement, and I think that sumptuous, gorgeous moment is earned not just by the song, but by the entire album that precedes it.
I think it's the kind of thing that wouldn't be possible to do without alienating a few members of the fanbase, but I think the most powerful art is often about risk. For the people who like what they achieved, it's broken eggs in an omelette. In that sense I'm just lucky enough to be one of the people who thinks Illumination Theory is fucking gorgeous and wouldn't have it any other way. Yes, it stops! It crashes to a halt. That's the point, and it's bloody wonderful. The song stops, but the story pushes on, and it wrings every last emotion out of that orchestra, gloriously, and when the band comes back in it's like hearing them through new ears.