Warning: major speculation based on a small nugget of information follows. Let's get the nugget of information out of the way first.
Possible spoilers for the truly spoilerphobic, but I don't believe this to be a real spoiler:
According to my sources Gwendoline Christie is playing John Boyega's commanding officer in Star Wars Episode VII, and she's mad that he deserted. She's looking for him. She's an antagonist.
UPDATE: I'm have new info that puts things in new perspectives. She's definitely hunting Boyega. I think she's an Imperial officer, but I got one more piece of information that puts everything in a new light:
The actress has been training with a lightsaber.
Could she be an Imperial officer who has a lightsaber? Or is it something more? I'm hearing the S word.
I believe this to be true. I believe she'll have some cool action scenes. What comes next is speculation based on very different pieces of info.
A couple of weeks ago a source told me that one of the characters who had been written as male/neutral in the script had been gender-swapped in casting. Was this due to the uproar about that first cast photo being very dude-heavy? I don't know, but I heard about this well after the uproar. And before the casting of Gwendoline Christie.
So that's part one. A guy role had been given to a woman, according to my source. Part two is that I'm hearing Christie is playing an Imperial officer. Part three is this: remember when we were hearing that Benedict Cumberbatch was in talks for the movie? That he was going to be a villain? His part was to be an Imperial officer.
Could Gwendoline Christie have the Benedict Cumberbatch role? That's pretty cool if so, and I do hope someone manages to get JJ Abrams on the record about whether or not the production bravely and progressively rewrote a male character into a female character. THAT is how you create diversity in a movie - you take a character who is not required to be a man and cast the best actor, regardless of gender, in the role. If this is true I hope JJ gets the praise he deserves.
There is one big caveat on this line of reasoning: Cumberbatch was in talks back when the Arndt draft was still in play. That script is gone, but do the basic concepts still exist? I know they had massive pre-viz underway, and I know that sets were already being designed/constructed. I believe it's possible that the Abrams/Lawrence Kasdan script incorporates many elements of Arndt's basic structure, but with major changes along the way.
Again, a lot of this is speculation. A lot of this is me hoping that Abrams is advancing diversity by hiring a woman to kick ass in a role that is essentially gender-neutral. I do feel very secure in what role Christie is playing, and I think she's going to end up being a great, very active, very threatening character.