Worst Star Wars: Rogue One

Not necessarily true. George Lucas technically co-wrote the screenplay of The Empire Strikes Back since the drafts he wrote alone became the basis for the film before Lawrence Kasdan came along to polish it. Leigh Brackett's screenplay was tossed out, but she was given an arbitrary credit because she died of cancer. The same thing occurred during writing of Return of the Jedi with Lucas writing an outline and draft before Kasdan and others made their contributions.