So it's obvious that either Hera, Sabine or Ahsoka are going to star in this, right?
I don't get that impression at all. Given the characterization of this as "Zero Dark Thirty" in the Star Wars universe, I can see Felicity Jones playing some sort of Rebel intelligence agent who is working undercover in the Empire to learn more about the Death Star. That in turn would culminate in a military raid to secure the plans. The inclusion of Bail Organa would be most welcome in my book.
My own hopes? I would absolutely like to see the film incorporate some of the Wookiee slave laborers who past EU has said were forced to work on the construction of the first Death Star, and how that might play into this story. And I certainly hope that the film would end with the Death Star plans being handed over to the crew of the Tantive IV, along with Leia, Captain Antilles and the droids.