I'll be in agreement with
@Nick--a reset allows everyone from the writers, directors, and actors to start fresh with the takes of Marvel that they wish to have. I also think it'd actually be important if they want to make a unified universe where Mutants are seen at large and not just as a "beginning" group of people.
Combine it with merging the Sony Cinematic Universe into one umbrella; and that allows you to have a universe all at once that can tell stories based with F4, X-Men, Spider-Man, Avengers, and a new set of Guardians right from the getgo.
Pull from more recent elements of media and comics even; like Peter Parker being an older Spider-Man in his prime (like Sony), and position him as the Iron Man of the new universe; and I think that'd be key.