I have to imagine that if the deal goes through, some X-Men films will stay in development with the goal to have the characters interacting with the rest of the MCU. Kind of like what Marvel has done with some of the characters they "got back" once they became an actual studio such as Daredevil, Punisher, Spider-Man etc.
Disney does dominate in a lot of ways- their remakes/sequels of their animated films, original animated stuff, Pixar, Star Wars/Lucasfilm, Marvel, theme park related stuff... Their library is crazy.