"I think they've got the hardest task, I think, out of all the films that I heard about that one is probably the greatest challenge", Edwards said, before proclaiming, "They're gonna knock it out of the park, but I wouldn't have had the balls to do that".
Speaking with Entertainment Weekly, Whitta finally revealed the details of this written and quickly abandoned version. They jumped away and later [Leia's] ship came in from Alderaan to help them.
The most intriguing thing about this revelation is that Jyn and Cassian who would have been desperately trying to escape from Darth Vader in the film's climatic moment, instead of a group of rebel soldiers. Naturally, it would have been Jyn Erso and Cassian Andor. But they assumed that the Disney machine wouldn't allow that, what with its desire for unending sequels and the hope that children don't leave the theater fully traumatized. In this ending, he's just as tenacious, but Jyn and Cassian escape in pods before their ship is destroyed by Lord Vader. "The pod looked like just another piece of debris ..."
Gary Whitta, one of the Rogue One screenwriters, confirmed that while the initial instinct amongst the script doctors was that "everyone was supposed to die", some of the Lucasfilm brass wanted some of the protagonists to live to fight another day. "The ship-to-ship data transfer happened off Scarif", he said. We had to find ways to compress the third act, which was quite long as it was.
"The next spin-off is Han Solo, that's another familiar character, but I think increasingly you're going to see..." It is totally possible that 10 years from now numerous new characters being introduced (Knights of Ren, Guardians of the Whills, Saw Gerrera, Maz Kanata, et al) will be popular enough to warrant their own spin-off films, or possibly a movie with exclusively new characters, vehicles and planets could spring from the mind of a gifted filmmaker looking to reshape the brand. That was some of the reinvention that happened.
This observation (and that sweet Disney money) led to those much-talked-about reshoots, which significantly altered the climax and kept Jyn and Cassian in one building for the final act of the film.
However, there were many things that changed between Gary Whitta's first draft and Chris Weitz's revisions. There's no way Disney'll let us do that.