Re: FOX Shared Universe
I think a X-Men/Fantastic Four team-up film could only rival the appeal of Avengers. Not in terms of box-office performance, but the appeal of superheroes from separate franchises working together.
Even if DOFP is a mash-up of the OT/FC cast, people easily saw the films from those two casts as X-Men films. Then if X-Force is gonna work with the X-Men in the future, people will just see it as the X-Men spin-off working with the main X-Men team.