I have to admit that if SC hadn't been the second DT album I'd bought, it would have been a massive curveball for me, but as it was, I hadn't really any ideas of what DT sounded like other than what I'd heard on SFAM.
Admittedly, a lot of the songs have an intro-verse-chorus-verse-chorus-soloing-chorus-outro sort of structure, with TDEN having prechoruses and PoW having that spoken bit rather than a solo. That said, ItPoE has a very non-standard structure, and you've got Repentence, so really, the structure does differ quite a lot, although maybe not curveball structure for DT.
But yes, stylistically, it's pretty unusual. So, I would not be surprised if the next album did have some, or even quite a bit, experimentation. I would be pleasantly unsurprised. That said, I very much doubt it will suddenly turn out to be a dark ambient album. That would be really wierd.