Rogue One didn’t require a thorough understanding of the OT in order to enjoy it.
I guess not, but if I wasn’t already a Star Wars fan, I’d have no interest in this movie and probably wouldn’t have cared much about it if I did see it.
I have no problem saying that R1 is a movie made for Star Wars fans. If someone starts here and wants to watch the rest afterward, that’s cool, but I feel it was made for people who already dig Star Wars. And that’s fine.