While there are some bigger villains who could cameo in Rogue One (and I'll get to those in a bit), one of the most crucial when it comes to running things on a base level in the Death Star would be Grand Moff Tarkin. Wilhuff Tarkin was in charge of the construction of the Death Star, and the highest ranking officer among the Imperial ranks, so having him on-board the space station isn't just something that would make sense, it's almost a requirement given his character's position at the beginning of the saga, and where this film fits in the timeline. There were rumours last year that Tarkin would be recreated for the movie using CGI, with complications due to the fact Peter Cushing wore slippers rather than boots on set (meaning there was no model for his feet), and though there's no confirmation on that, it would regardless be a tough task for any actor to follow in those footsteps, no matter how comfortable the shoes are.
NCTJ-qualified journalist. Most definitely not a racing driver. Drink too much tea; eat too much peanut butter; watch too much TV. Sadly only the latter paying off so far.
A mix of wise-old man in a young man's body with a child-like wonder about him and a great otherworldly sensibility.