I thought it was a very good example of the genre of 'rewriting a well-known story from the villain's POV, and making her the good guy' and I thought they did a passable job of rewriting the origins of all the characters from the original movie.

I have no hopes the movie will be any good and don't plan to see it unless I hear differently from people I trust.

If you want a good story in the genre, read Till We Have Faces, C.S. Lewis' retelling of the Psyche/Cupid myth (Cinderella, essentially) from the point of view of one of the wicked stepsisters. This book may be the ur-example of the genre, actually. I read it to my wife (Cinderella is her favorite) and she loved it. Lewis does a great job of giving the stepsister reasonable motivations and her 'wickedness' is just well-meaning overprotectiveness and lack of trust in her naive stepsister Psyche.

Maleficent and Frozen are only partial versions of this trope, in that they don't really make the villain the main character. In Maleficent the main character is the princess (or at least 'as much primary) and in Frozen the little sister is the main character, trying to save her misunderstood big sister.

I am trying to think of other examples, and I can't. There must be more, right? Is every story in this genre rescuing a female from villainhood?