Coming from official Dex Team update published on their KS:
Both the Wii U and Ouya versions are still very much in development and our target release window is Q1 2016 (possibly Q2 for Ouya). We realize that this is later than first anticipated, and that those of you waiting for these versions to play Dex are getting impatient. The main reason for the delay is that we decided to work on the Enhanced Version of Dex to improve several aspects of the game, based on the feedback we received following the release. The console versions will of course include all those changes (and more), so our development schedule was significantly shifted as a result.
Nintendo has been extremely helpful and delightful to work with, and we’re very excited about the Wii U version, which will feature some unique functionalities, more of which we’ll detail in the coming months.