If they did it would be a reboot.
Various reports are saying FOX wants to reboot so they can retain the rights. Similar to what Sony is doing with spider-man
That's what I heard as well. But so far FOX only announced that they've hired a writer for the job, and there has been no activity regarding this reboot at all. I wonder if putting the movie in pre-production is enough for FOX to retain the rights, and if so Marvel will probably never get it back because they can keep it in perpetual motion of writing and rewriting without actually making a movie about it. If FOX is indeed making a reboot, I hope they will make it in the same quality as X-Men First Class, but I still prefer to get the rights revert back to Marvel if I can have a say in this.