While I did love Jean being a leader I don't mind if she doesn't stay a field leader. She was great in X-men Red but in Disassembled she mainly floated around and ordered others. She didn't always fight even when it would have made sense for her to (for example fighting the dinosaurs). Even in Red sometimes she just floated around barking orders instead of fighting (ie the fight with the Sentinel). I want to see Jean doing something. She has one of the strongest powers! I'm conflicted. I think Jean will be a leader but I'm not sure if being a field leader is the right thing for her.
I also agree about Emma. They worked well in Dennis Hopeless' Jean Grey solo and I would love to see them work together again. I think there is a mutual respect between them though they will never be best friends. Emma knows Jean is powerful and Jean knows Emma is a force of nature. They also know they care about mutants, and their students. They both love Scott and both have had traumatic experiences with the Phoenix. They have too much in common while still being very different and distinct characters.