Yesterday we learned how bad the first draft of Rogue One really was and now more information about that draft of the film has come out.
Aside from the fan favorite Vader scene not existing then (as it was actually a good addition), the big revelation is that Vader killed Krennic at the end of the movie. Basically Krennic escapes the Death Star blast on Scarif, and just when he thinks he got away with his life Vader end him.
I think Tarkin, who had a real bad history with Krennic, killing him with a superlaser blast to the face was a much more poetic way for the guy to go out than Vader simply killing him. He ended up being killed by the very weapon he spent years working on. It’s another example of why it was a good thing that Lucasfilm brought in a better writer to do a second take at Rogue One.