Isn't Storm going to do just that though ? Leaving the X-verse to roam in the broader Marvel Universe ? At least that's how I interpreted it in the interviews. So, why not Rachel ?
I mean, we are all on the same page here about her being mishandled in Wood's X-men, and that's the best showing she currently has.
I'd rather have her baby-sit her alt-futur husband on various space/science adventures rather than being dragged down like she is at the moment.