The equivalent of the scene that plays before the opening credits of a TV show. In the same vein as Willrow Hood’s post about post-credit scenes.
Though not impossible, I guess the issue with this in SW films is the crawl kinda explains the important info you need to follow the main story at the point you join it. As Rogue One showed with its flashback opening 20 mins.
The opening scene is not a flash back. It’s the rest of the film which is a flash forward. Period !