I don't know much about dressage at all but that looked pretty good. The horse looked much more comfortable than most I have seen on TV.
If she was really interested in doing reining at the WEG, I would think that she would be interested in taking the time to properly ask for a sliding stop or a spin. No a horses mouth should not gape open like that (it did it every time she took up the reins, even to change pace for the circles). Not the horse's fault though, her reins were way to short and she was manhandling his mouth. She clearly never learned how to ask for a sliding stop, the horse was hollow, high headed, and hopped during the stop. Plus he stopped more on the front than the hind. In the spin, his pivot foot was everywhere. Just cause he is turning really fast doesn't make it a spin. :( The only defence I can think of that she may have is that she got a not-so-well trained horse from a no name trainer because none of the really good reining trainers would let her ride one of their horses. LOL.