I actually like that idea. Jean Grey becoming headmistress of a school named after her...something about that puts a smile on my face.
Sadly, I think that's one of those ideas that would just make too much sense right now. As I said before, adult Jean is going to stay dead until the story with the time displaced X-men concludes and that may be a while. Now some have questioned the merits of telling the story of O5 Jean rather than adult Jean. I can see their point of view, but I suspect that the reason Marvel is going this route is because they don't want to tell more stories about Jean Grey and the Phoenix Force. I also suspect they don't want to go through the same emotional roller coaster with her, Cyclops, Emma Frost, and Wolverine. I completely get that. We've seen so many of those stories before and we don't need to pile onto them. Having a time displaced Jean Grey allows them to basically start fresh without rebooting or retconning anything. They can focus more on Jean Grey the person and not all the complications surrounding Jean Grey. What I really like about All New X-men is that it shows Jean Grey in a painfully human and painfully immature way. I think that has been refreshing and it has made for some of the best Jean Grey moments in over a decade. I still want to see an adult Jean Grey return at some point, but for now I'm okay with more stories featuring a teenage Jean Grey.