5 Mutants That Have Never Been X-Men (But Should Sign Up)

The son of Mister Fantastic, Reed Richards and The Invisible Woman, Susan Richards nee Storm, Franklin is a mutant. Born with the power to shape and control time and space (appropriate for the son of a famous time traveler) Franklin has been many ages and at various different power levels all of his life. He is aware of the X-Men and has worked with them, most notably during the Onslaught saga in which his powers were sought by the titular villain. Franklin saved the world that day by moving the Avengers into a separate 'Counter-Earth' using his reality warping powers. Franklin has become much more of a developed character since Jonathan Hickman and Matt Fraction have been writing him, but as a mutant child, it would be so interesting to see him at the Jean Grey Institute as one of the students. His sister Valeria (who may or may not be a mutant) when developing her super intelligence theorised that by telling the family about her new abilities, she risks alienating and ostracising Franklin. This would be a perfect way for Franklin to step away from the Fantastic Four and start his training as an X-Man. The advantages would be clear for both sides in this arrangement. Franklin would attend the Institute and learn how to develop his powers at the same time as learning valuable combat and leadership skills. The X-Men could be occasionally brought in to tackle threats more suited to the Fantastic Four, such as Annihilus and even Dr Doom, making for new and different stories as the characters find themselves in new situations. The stumbling blocks to what I feel would be an exciting idea, would be the in-world story of Reed and Sue and whether they would leave their eldest child with Wolverine, master assassin and berserker, although they have a loose history with his son, Daken. I could see Reed trusting Storm and the other X-teachers and i'm sure he would trust Wolverine to look out for Franklin. There's just something that doesn't sit right. If Professor X was in charge, I feel this would be easier but I suppose now that Beast has joined the Illuminati, Reed might feel better about it. The types of stories that could be opened up with the Fantastic Four would be interesting to see and read (imagine if whilst Franklin was with the X-Men, the F4 has another child or grew older) and would also allow the X-Men to be compared to them in terms of acting as a family. Lets also not forget that one of the teachers at the Institute is Rachel Grey who has a bit of history with him...or future kind of him...