I have a feeling people will still refer to the films by its respective episode number rather than it's title. The PT and OT have been promoted that way for 15 years so it has been ingrained in everyone's head.
but for 19 years before that, the OT was promoted as "Star Wars", "Empire", and "Jedi". If GL was able to change what people call them, Disney can just as easily change it back.
That's true, but it will take time if this is what Disney really wants to do. I'm guessing the majority of fans that exist now going into the ST are from the SE/PT/revisionist era who have gotten used to calling the films by the numbers. Won't be easy to change that.