Really interesting interview with Simon Kinberg, the co-writer of X-Men: Days of Future Past and the upcoming X-Men: Apocalypse. SPOILER HEAVY. DO NOT READ IF YOU HAVEN'T SEEN THE MOVIE.
The really interesting reveal is at the end where he says that, where DOFP was a mashup of time travel and superheroes, the next movie will be a mix of superheroes and disaster movies. And I was thinking, since we've heard that Apocalypse will be set mostly in the '80s, and since the First Class movies tend to mix alt-history with mutants, maybe the disaster will be...
Think about it: superpower tensions were extremely high during the first half of the '80s, and the danger of a limited or all-out nuclear war seemed terrifyingly real. And since Apocalypse is, well, Apocalypse, it only makes since that he'd want to create some sort of situation that would kill off most of the regular humans and leave the strongest mutants in charge. We don't know what the altered chronology of the "good" future looks like... maybe something really bad happened thirty-odd years before that caused humans and mutants to find common cause. I'm guessing that maybe the next movie is set mostly in 1983 or so and involves some sort of international incident — similar to Soviet fears about Able Archer — that triggers a nuclear conflict. And hey, maybe we find out Gorby's a mutant!