In a recent interview with Comicbookresources, Peter David had this to say:
CBR: In this arc, you’re returning to a character you created, the Maestro incarnation of the Hulk. How does it feel to return to the character? What made you want to pit him against Miguel?
PAD: Because I’m working on an upcoming project featuring the character, I decided this would be a good time to bring him back into the Marvel Universe. And since I knew that Miguel was returning to 2099, it seemed a good time to bring him in.
With the upcoming Secret Wars limited series, there are a lot of new short term comics based on various timelines, so maybe there will be a return to the Future Imperfect world. How awesome would it be if Dale Keown was the artist too.