343 Executive Producer sat down with CVG for a Halo 4 interview and had this to say about the possibility of a new genre:
"We've always had a big vision for Halo and the universe and we look at ourselves as not just a games studio but an IP studio," she said.
"The first-person shooter is the best place to tell one kind of story but as you can see from Forward Unto Dawn and stuff like that, there are other parts of the story that are interesting to tell in different ways.
"Forward Unto Dawn allowed us to explore characters a little bit differently and tell a different kind of story - and that is interesting to us. We want Halo as a universe to grow and evolve and be a Star Wars... all the good parts about Star Wars!"
She added: "I think we'd look at what the most interesting genre, medium, delivery mechanism is to tell a certain story, and if it moves the IP forward in an interesting way we'll do it."
So a new medium for the story is not out of the question. It just would require some delicate approaches.