Ok, I'll rephrase the question then:
...you said Dream Theater were "pushing the boundaries of traditional musical concepts." Are you going to explain what those traditional music concepts are, and how they DT expanded on them? ... I mean, what's the big revolutionary idea behind SDOIT, then? They wrote a suite, but had the balls to call it "one long song?"
Even though you were not responding to a post of mine, I would like to comment on this, if I may:
You're right, there really is nothing revolutionary about Dream Theater writing a 42 minute, 8 movement piece of music and calling it one big song. Composers have been writing stuff like Six Degrees for centuries. What
is revolutionary about it, however, is the fact that it is a
rock/metal 8 movement, 42 min piece of music. Now in and of itself, that is nothing original per see; prog bands have been writing stuff like this since the 70's, but it is worth pointing out that in the world of rock as a whole, the idea of constructing a single, epic composition like 6DOIT divided into multiple parts is still fairly rare. I think as prog fans, we tend to take for granted that bands will do things like suites, concepts albums, rock operas, 20+ minute epics, etc; but in the world of popular music, such ideas are relatively few and far between. And for a band like Dream Theater, a band that increasingly has appeal to a younger, more modern oriented fanbase, things like 6DOIT help to intoduce those concepts to a whole new generation of music fans that were up until now relatively unfamiliar with them. Even today, most younger metal/prog fans I know have their minds blown by things like ACOS and 6DOIT, and even people 20+ years old, whether their musical cup of tea is Motley Crue, Nirvana, or Disturbed, are still reasonably unfamiliar with the idea of a "rock epic". For a band like Dream Theater, a band that while not necessarily mainstream still has a wide enough appeal to be drawing in otherwise mainstream music fans, things like ACOS and 6DOIT are relatively ballsy. 6DOIT may not be revolutionary in the sense that no one had ever done something like that before (Fates Warning wrote A Pleasant Shade of Grey a scant 5 years before DT wrote 6DOIT) it is a safe be that there are far, far more rock/metal bands would much rather stick to musically distinct individual 3-4 minute songs, thus making 6DOIT quite revolutionary indeed. It may not be a new idea, but in the world of modern rock, it is a rather uncommon one.