Rogue One was a hit from every standpoint. Critical hit, praised by fans, and smashed box office records. Including being one of the highest grossing films of the year, even beating out films like Captain America: Civil War in some aspects. However, eagle-eyed fans will note that a lot of scenes show in trailers and previews were not in the final film. Please note that spoilers may follow.
There was a lot of backstage drama that apparently plagued Rogue One at times. There were numerous reports of reshoots for various scenes, and between the cast and crew confirming that did happen, and the trailers having scenes not in the movie, you have to wonder what happened, at least in part. Director Gareth Edwards talked with Empire Online about a lot of things in Rogue One, and the “deleted scenes” was one of them.
He notes that the final act of the film, where the Rebels and Rogue One crew went to get the Death Star plans, needed some refining, and a lot of shots were taken in the process of that. Certain aspects apparently “fell away” as time went on. Certain shots were left behind, leaving possible big scenes a mystery. For example, one key trailer showed Jyn Erso staring down a Tie-Fighter on the communications tower, that got cut. A scene where Jyn C-250 (who died early on in the act), and Cassian had the Death Star plans and were running down the beach seemed to indicate the final push would’ve been there, and not on the tower, but that was subsequently cut.
So why did those “non-canon” scenes get put into the trailers? Well, as Edwards notes, it was good for marketing, and it’s hard to deny that though we didn’t get to see those scenes in context, those trailers did indeed help make Rogue One what it was.