Yes! I'm double excited for DT12 now, if there's going to be orchestra.
*EDIT*
Orchestral arrangements have become a cliché in metal, but I bet (or at least hope) DT will be able to use them effectively. Eren is really lucky!
Dream Theater are better than most in incorporating orchestral arrangements into their music, I mean, look at Octavarium, Sacrificed Sons, all of Score (besides tuning problems at times), not to mention Jordan Rudess is a classically trained musician and composer. He also brings the prog most likely the most, and is quoted for not having much interest in metal music. DT are much more than a metal band. I wouldn't be surprised if this album is less on the metal and more on the prog, though heavy much of the time I'm sure. But I honestly don't know what they'll do on the next album now that there's going to be some symphonic music.