Maybe they tried to leave stuff un-played, to save it for future tours (in case they don't want to overplay/repeat many songs). I guess that's what they did with "Behind The Veil". Since I first listened to that song, I always thought it would be a great closer for a show. Maybe they agreed with me, and saved it for their 2015 tour with that purpose. So, it seems obvious to me that they'll play "The Bigger Picture" and/or "Surrender To Reason" in 2017/2018.
I suppose I understand this, I just tend to think there's no time like the present for playing new material. I mean, you're advertising it as the tour supporting a particular album, people are expecting it, why not play that whole album, especially when it's not a double album like
The Astonishing and therefore more or less just half of your set. I understand leaving stuff out under certain circumstances, like Space Dye Vest, but I think you should make an effort to do the whole thing, just because if you don't play something, it's so easy for it to lapse. Like if the band didn't play Build Me Up, Break Me Down or Outcry or Beneath the Surface on the ADTOE tour, they might have never made it to the stage. They may not ever get played live again. Because in the future, when they want to pick a song from ADTOE to have in the setlist, it's going to be On the Backs of Angels, or Breaking All Illusions, or Bridges in the Sky, or This is the Life for a ballad—the other ones are unlikely to make it. Now, I think The Bigger Picture will indeed make the stage, but I think it's better to bring the whole thing out at once and not risk leaving them in the dark forever. This is especially a risk when you have a static setlist—probably wouldn't have been a big deal during the MP rotating setlist era.
Now, of course, I know why some bands don't. Iron Maiden played their whole
A Matter of Life and Death album in 2006 and 2007, but the problem was that it was their 14th studio album, so a lot of fans didn't know or care about the new release and just wanted the band to
play classics. But Dream Theater shouldn't have that problem for the most part, because their fanbase is much less classics-inclined (since DT never had a big hit) and more likely to care about the new album, so I think they should always play the whole thing, as they are doing right now with an album twice as long as DT12. I just really hope that all the songs they missed get played on the DT14 tour (along with the whole DT14).c