As I said, this should be a movie set in the Star Wars universe, not a Star Wars movie. There’s the Star Wars style and the Star Wars universe. They are two separate things. Comic books and video games are invariably trying to give you the experience of reading or playing a Star Wars movie. The crawl helps to further that aesthetic to bring them closer to the Star Wars style (despite not being the medium the style belongs to). Notice games like Republic Commando, which try to replicate the Star Wars universe but not style, are devoid of crawls.
Rogue One’s goals are completely different. The aesthetics that are important there are the in universe ones. A crawl is a presentational aesthetic, not an inherent part of the Star Wars universe. If Rogue One is going to break from the Star Wars style in so many ways (if it’s not totally chronological, if it’s devoid of swashbuckling, if the music has a different tone, etc.), then it doesn’t make any sense to keep a key element of that style, the crawl.
I will say, and I’ve said it before, I do think it’d be a mistake to ditch the “A long time ago…” card. Less an element of the Star Wars style and more a signpost that tells you you’re about to enter the Star Wars universe. So it’d make sense to keep that consistent.