X-Men: Days of Future Past hasn't been released yet, but the hints and speculation about the next X-Men movie are already out there and picking up steam. Back in January, Hollywood Reporter published 20th Century Fox's intention to release X-Men: Apocalypse in May of 2016.
Since then, there's been rampant guesswork about who will appear in the movie and how director Bryan Singer intends to bring everything and everybody together to fight the iconic villain, Apocalypse. A multi-film crossover concept is also being beach-balled around the internets wherein Apocalypse's story unfolds through not only the X-Men, but hinted at through Days of Future Past and the X-Force movie being talked about (bring on Cable!!).
It's been recently confirmed that Days of Future Past is more of a X-Men: First Class sequel and that principle characters, Professor X (James McAvoy), Magneto (Michael Fassbender), Mystique (Jennifer Lawrence), and Beast (Nicholas Hoult) are inked for the Age of Apocalypse-based movie. Shortly after that was released through an interview with Singer, there's also been a strong indication that Hugh Jackman will also return as Wolverine as well as the third Wolverine movie. In fact, collider.com's article points out that producers, Lauren Shuler Donner and Hutch Parker, are trying to schedule movie shoots either concurrently or very close to each other.
Comic Book Resources and other sites are reporting that Singer is also talking about being able to bring back younger versions of Cyclops, Jean Grey, and Storm. Singer's terms his concept as that of an "inbetweequel" where the story moves from DoFP toward his original X-Men movie where those three characters are instructors at Charles Xavier's School for Gifted Youngsters. Both Gambit and Nightcrawler are also being mentioned as possible inclusions for Apocalypse.
Who do you want to see in the roles of Cyke, Red, and Storm?