Also, to the "fat and bad are synonymous for Disney women", I offer my rebutal : Maleficent and the Queen from Snow White.
Not to mention that the Queen from Snow White, and in some ways Maleficent, have often been fetishized and viewed as attractive in a femme fatale sort of way. Even to the point where Maleficent not only got her own film, but is being played by Angelina Jolie.
I think there's a tiny bit of reversal, thanks to Frozen. Elsa becomes queen, and the only real threat at the time is that she can't control her abilities. She's not malevolent herself. She's most definitely loved and appreciated by the end of the film.
Frozen is basically one gigantic reversal of every bad trope and stereotype Disney princess films have used over the years. Among others:
* Familial love and friendship are a "true love" just as much or more than romantic love.
* You shouldn't jump into a relationship with someone you just met the same day, and ESPECIALLY don't jump right into marriage; you don't know each other nearly well enough and they probably have some bad things hidden from you.
* Everyone is flawed and you can't just fix everything. But that's okay, and you should just try to fix the things that can be fixed and love the people that you want to love in spite of their flaws.
* You don't need a tough man to save the day. Women can do it themselves.