I watched it last night. Very sad performance. I too thought she must be drugged, drunk, or suffering from a very bad case of anxiety or something like that.
While Brit surely blew this one, I think if she gets some rest, gets herself together, and practices, practices, practices, she can still have a career in the future. It just may not be the same as her career was before.
On the whole idea of the "star" not really doing much and a whole lot of other dancers dance around them on stage: Cher does this, and she does it very, very effectively. (Of course, she is 60!) I went to see her on her "farewell tour" and she kind of just stood there and swayed to the music and her dancers did the dancing. She wore heavily fringed costumes that moved a lot, and the entire efffect was areally good. Plus, she walk/strutted across the front of the stage a lot. There was a whole lot of action going on all around her at all times, with dancers and acrobats. All in all, the effect was great.
So maybe Brit could find out who produced that tour for Cher and get them to help her. And they could also help Brit with costuming. While I did not think she looked fat-fat, she could have been professionally costumed in a manner that would have made her look GREAT.
At this point, I do feel sorry for the girl. I wish her well.