Re: What would you rather see next - FIRST CLASS 2 or X4?
A real lover from the comics, its characters, arcs and themes, should know that both sequels could end being great movies, done by the right director.
But thinking more like a studio executive that is happy with FC critics and boxoffice to date, the sequel to FC would be the most logical option right now. The audience has loved the movie, so give them a continuation and see how it works. It has a big potential in terms of boxoffice, so Fox shouldnt let it die just with one prequel.
Next Big X-Men Crossover
* 2017- X-Men: Age of Apocalypse
Edit: Forget about 2017:
Official announcement -> X-MEN: APOCALYPSE - MAY 27, 2016!!!!