If from what I remember and someone may correct me, but Fox can't reboot X-Men or they lose it. If that's the case it pretty much a lost cause because that universe is all over the place. Maybe they can get around it with some type of mutant that can reset the past but even then I don't see them pulling in Disney money.
Plus, I think you run into the some of the same problems DC has run into. One is do you build slow or fast. If you build slow, will people have enough money or time to go see 3 or 4 movies in theaters that will build up to make a mega movie while both WB and Disney is doing the same. If you build fast, do you sacrifice story lines or put to much into one movie. Another issue I think they run into is their characters might be to iconic. One thing I think Disney has going for them, is the characters they started with are B & C tier characters. People probably knew the names of the characters and some of the background but more or less have built their relationship and grew with these characters through the movies. A-tier characters don't get that luxury. "Superman can't do this." "Batman can't do that." "Spider-man wasn't this." "X-Men wasn't that." Everybody knows the background and have ideas on what the characters should be so they can't really deviate to much to tell the story they want to tell. Last thing is brand image. Disney has this down pat. Everybody trust them no matter who or what they put on the screen and know its building to something bigger for the end of each phase. I'm a DC guy. After BvS, even though I liked it, they are going to have to get their brand back up in the public eye. They got a chance when they bring back Supes to change the character and fix issues people have with him. Fox is going to have to do the same thing with branding and most of their characters. They either wrote characters with to much fan service in mind or keeping certain actors around and its hurt the product.