One of the things I did love about Rogue One was the idea that the Force was this mystical power and how people treated it, who may not have been on the light or dark side. I forgot the blind guy's name but he was always saying "I am one with the force and the force is with me". Something I got from this teaser is that theme might continue in Last Jedi and I'm really intrigued by that. It would also make Rogue One really part of the Star Wars mythos instead of just anthology film.
Chirrut.

Well, even with the Protectors of the Whills (the group Chirrut and Baze were a part of), the Nightsisters from the Clone Wars, the Bendu and the Lasat from Rebels... they're kind of heading in that direction. Besides, the Force was a mystical power before we got the prequels. I think its great they're bringing that back.