Not to rant but I've figured out my problem with the concept, I was thinking this over and trying to decide why I have such a problem with this and its because it's too gimmicky. Let me start by saying I think that it does have potential however ideas like this need at least a three year plan a way to get from points: A, B, and C, and most of the time there isn't one its just contrived. It also brings to mind the inevitable retcon that will come to reverse it when Bendis is done with his "toys".
And it also stuns Adult Jean's growth when she, as we all know, comes back because she either won't deal with the things that has happened since her death and reversal to "teenhood" or simply forget about everything she's lost which could of made for incredible stories the type of stories Jean needs. I've said it before and I'll say it now Marvel is solely responsible for all of Jean's missed opportunites anytime something organic or character driven is pitched for her its immediately REJECTED.