18. Obi-Wan Was Almost In It
Rian Johnson admitted after the film's release that he did toy with the idea of having Obi-Wan Kenobi appear as a Force ghost instead of Yoda (Frank Oz), yet rejected the idea for one major reason: casting.
Due to original Obi-Wan actor Alec Guinness having passed away many years ago, Johnson would've had to either use a CGI double or simply bring Ewan McGregor into the fold, and while McGregor was eager to reprise his role, Johnson wasn't quite convinced.
Ultimately Johnson felt that having Mark Hamill interact with the McGregor version of Obi-Wan - an iteration of the character he's never shared the screen with before - wouldn't feel authentic.
As fun as it would've been to see Obi-Wan in the movie, Johnson was probably right here - we got to see Yoda instead, and McGregor finally got to reprise Obi-Wan in the recent Disney+ limited series.