I think this one will under perform and they'll reduce the budget to future installments (this one has big budget, but it's less than Into Darkness), if not consider taking the film franchise in a new direction.
Standard Internet reactions: (My responses) Fire Singer. (Yes, the guy who made the first successful Marvel superhero movie) Give rights back to Marvel (so Marvel movies can become even more convoluted cross-overs) Mystique is not an X-Man or the leader of the X-Men. (Seems like mutant characters switched sides a lot) It's J-Law's fault for being a bigger star now. (Nerds decided they hate her.) Costumes aren't comic book-accurate (Somethings don't translate well into live action) Why have none of the characters aged since last film was in the 70's and this is the 80's. (They want CGI Patrick Stewart back?) Apocalypse isn't fearsome/large/threatening/whatever-enough. (At least he isn't some normal human guy in a business suit or some cop-out) Of course can't have an X-Men movie without him. (Whatever)