Star Wars: Rogue One - 10 Simple Blunders That Would Ruin It
9. An Ending Teasing A New Hope
Rogue One is a prequel. Not in the sense that makes that word taboo for Star Wars fans, but it is still set prior to the events of the original film. This shouldn't really pose too much of an issue, given how the vastly different set of characters and locations mean it's not just filling the gaps in a known story, but there's still a chance for it to repeat one of the biggest prequel sins imaginable.
Some of the worst prequels (I'm looking at you Red Dragon) think it's smart to directly tie themselves into the events of the original movie, forcing in an ending scene that takes you right to the beginning of the earlier film. It's prime fan bait, but really only ensures the film never escapes being a prelude; it makes little sense if you're watching things chronologically and if you know the original it's just eye-rolling.
Revenge Of The Sith had the smarts to pause twenty years before A New Hope and, while it did tie things up a little too neatly, that meant Episode III felt like a complete journey in and of itself. With Rogue One there's going to be ample opportunity to end with a character beaming the plans to the Tantive IV at the very last second, ending with a cheeky shot of a woman dressed in white with buns getting them on a disc. Which just be a painful final scene.
By all means show that stuff, but don't make the ending of the whole film a blatant tie-in and forget the story at hand.