You'd have to specify which of the multiple contests she's lost.
She invariably has to improve at some point; otherwise, she's not going to have character development.
She also released Ambipom, a true wtf moment since it was undoubtedly her best Pokemon.
She hasn't improved too much, as she still often slips. However, she takes risks, which is integral to the growth of any Trainer or Co-Ordinator. She's not staying safe by using just one Pokemon and sticking to the formula that won her the ribbons she's won mostly because half of that formula's not on her team anymore, but she's definitely better than she was in DP001.
Now, if only her personality would improve...
And Piplup...
And Buneary...
Well, she's a work in progress. Slow, barely noticable progress.