The idea of FOX giving all of the X-Men and Fantastic Four rights back to Marvel is a beautiful thought, and brings a single tear to my eye, but they will go out kicking and screaming before they let those rights revert. They've finally, after fifteen years, started to branch out beyond X-Men and Wolverine films with the failed Fantastic Four reboot, as well as the upcoming Deadpool and Gambit solo films, but they're likely to go further into the mutant world, and possibly dig into some of these spin-offs from the traditional X-Men series!
The X-Men are well known for being very diplomatic about their enemies before jumping into the fight, but not all mutant teams are the same. One of the most famous characters that Fox has the rights to who hasn't yet been utilised in the films is Cable, so why not introduce him to assemble these guys Nick Fury style? Colossus is already getting revamped and recast for the Deadpool film, so they should continue to use him! I doubt all of the original X-Force characters would be in the film, but taking a selection of characters from the X-Men films would make up a great team!
While the majority of mutants we've seen in the films have been American (or Canadian) there is a whole world of mutants out there, and Excalbiur is the British equivilant. Why not expand out further in this universe? Excalibur deals with a whole set of different threats and allows for the introduction of Captain Britain, who has long been famous in the Marvel comics.
3. New Mutants!
Something which seems "in" right now is young adult films, and therefore I am at a loss to explain the lack of Marvel using Young Avengers or Runaways, while DC refrains from utilising the Teen Titans (so far) and Fox doesn't delve into the world of New Mutants. Younger mutants could really make for a great film or two, and they are getting into that with the younger versions of famous characters in the upcoming X-Men: Apocalypse, but I think they should completely throw away some of those characters for a while and develop new ones.
One recurring factor of the X-Men films we have seen thus far is their struggle against the government. The first X-Factor series detailed a government-sponsored team of mutants, something similar to what Tony Stark wants out of Civil War. However, if Fox wanted to develop an X-Factor film, they could also go for the newer format which is more of a detective agency of mutants, which would still deliver a very different format to the films so far. The original team was formed out of the five original X-Men (Beast, Cyclops, Jean Grey, Angel, Iceman) which would allow Fox to continue with these younger versions of the characters they are introducing. Or the newer team has different members including Quicksilver (who we all want to see more of!), Polaris (who definitely deserves an introduction) and Havok (who we also want to see more of!)
So what do you think? Are these solid next steps for FOX? Or should they go for a completely different route?