I notice Harley Quinn is your avatar here. I take it you’re a Batman fan, right? So, is Batman really Batman without Bob Kane and Bill Finger? Is Paul Dini eligible to write Batman stories and whatnot? So Rian Johnson should be eligible to write a Star Wars film, no?
Batman is a franchise that has undergone many reboots and iterations that divulge significantly from the source material. Any writer can write a Star Wars movie, but they won’t be true continuations of Lucas’s core story. While I would like to believe that Star Wars could be different from other franchises and their multiple iterations, it really isn’t. So under that logic, there isn’t an issue with a George Lucas Sequel Trilogy being made after this one wraps up.