Sony has a ton riding on the success of their adaptation of The Dark Tower. The fate of a big screen and small screen franchise depends on the opening film being a hit, and while they have Matthew McConaughey and Idris Elba leading it, the prudent move is to take as much time necessary to get it right, and that's exactly what they're doing.
The Dark Tower has been moved from its crowded February 17th 2017 date to an undetermined date next summer. The reason is a sound one, and that's to make sure the visual effects are up to snuff and under budget, rather than rushing them and paying considerably more. A source tells EW...
“It’s a very fiscally responsible budget, and trying to stay in budget to make money and stay profitable means the VFX won’t be finished in time. Now that there’s more time, they’re not paying rush charges to get the effects where they need to be.”
There was a shoddy-looking trailer that leaked a few weeks ago and some have used that to cast early judgment on the Nikolaj Arcel-directed film. While I doubt Sony took the criticism to heart, whatever inspired them to slow down and make the best movie possible is a good thing.