I quite like her too, especially since seeing some of the strictly interviews she's done. I just get the feeling that she's got no dancing ability, combined with being embarrassed/not being able to 'let go'. Just because she's good at tennis or any other sport, doesn't make her automatically a good dancer, regardless of competitiveness.
I also wonder if it's all been a lot more difficult for her than she imagined it would be, every aspect of it. Perhaps she thought it was all going to be 'fun', and it's not.