I just saw where bushy eyebrows are making a comeback so perhaps you can relax on that front.
I think that her unpolished looks are part of the charm but realistically this competition is a job interview where she's trying to land the job of sharing the stage with greats in musical theater. In that light, she's going to need to be willing to look the part. I think a good stylist could give her some help without "losing" her. She certainly could use a little help with hair (especially up on top!), some tastefully applied make-up, a dress that works well with her skin color, and shoes that she can actually walk in.
She certainly shouldn't be done up like a size two pop star, but I think she needs to dress the part of the job she wants, like a Middle School Librarian Diva.
I've been surprised at how much access the press has had to her. Here the contestants on Idol are very tightly controlled. This is an interview of Piers which is interesting.
http://hollywoodinsider.ew.com/2009/04/piers-morgan-on.html