I love the idea of what their intentions are with this tour. I really wish more bands, nowadays, would take more chances with their setlist as oppose to relying on their "hits" or to them, their biggest album. To me, the closest I see where bands I see ever really go outside of the box with the setlist was Rush and Iron Maiden (Rush with their Clockwork Angels tour set and Iron Maiden with the shows they did for A Matter of Life and Death where they played the album in full).
The way I see it, I trust DT very much to give the fans, that are going to see these shows, something very enjoyable and memorable that will not be replicated again ever, years from now. Right now is the only chance, they are going to do something like "Dream Theater presents The Astonishing Live" and who knows if they have another chance to do something like that, and I'm pretty sure those that are not going only because DT are not going to play Metropolis or Pull Me Under or The Spirit Carries on, etc. are going to miss something special, I feel imo.
I'm sure the tour after this, though, they are going to back to maybe a more standard tour with a few new songs from whatever new album they are going to have, some staples songs, and some of the bigger tunes among the fans and that's fine, nothing wrong with that.