I was a bit surprised at first listen. I also have very vivid memories of what I was doing while listening. I went for about a 2.5 hour walk. It was a pretty warm day given that time of year here, but it was damp and misty out, and it was dusk. During the peak of Set 1, I happened to be walking in a giant park pretty much alone, since it was January, which was dimly lit by streetlights obscured by fog. It was kind of a perfect setting for the story, especially the part where Faythe sneaks into Ravenskill.
There were some parts I immediately liked. The intro to ALLB just wowed me, and still does today. I was kind of mad that they didn't keep going with that theme/style. I remember being horrified when the guitar solo for ANB ended...I wanted it to go on for another 5 minutes at least. ONW was a huge immediate hit.
I already knew I liked TGOM at that point, and I more mildly appreciated MOB.
However, I was a little bit uncomfortable with the rest of the album, because it was something different. But I got used to it quickly. It now ranks 4th on my all-time DT album list.
The thing about the album is the very best parts don't seem to go on for long enough. You get little samples of brilliance that this awesome band, despite how good things get, has never touched before. As I said, the intro to ALLB, the ANB guitar solo, that mega-epic 7-string guitar riff when Ravenskill picks up the pace that is good enough to base an entire song off of, etc. All of these were truly awesome moments of the album, and were also creatively unique and fresh, and yet the only last for a fleeting moment in the grand scheme of things. I even think some of the NOMAC tracks would have been really cool if they were turned into an actual track (I love that kind of ambient electronic music).
With that said, it's clear that this album got their creative juices flowing. They got to write some epic melodies and harmonies like they've never done before, and experimented with a number of new styles.
The album as a whole is, as Bosk says, easier to digest if you just say, "okay, I'm now going to listen to this Broadway musical soundtrack with a bit more classical influence than normal" instead of saying "Time to rock out to some run of the mill DT." I think once you adjust your expectations like this, it's easier to appreciate how much of a masterpiece this is, with so many layers of complexity, including the choir and symphony in the background.
But I'm still left with this frustration. Some of the coolest and most unique little clips of music they've written lately are very fleeting. Aside from the TA portions above, the DT12 easter egg is another one of them.