Basically the movie is about Anna. She's the princess, after all; she's bubbly and practically a cartoon version of Lucille Ball.
I think you're right, and that worries me since my daughter is infatuated with her! We have the Disney Infinity Frozen set and she plays as Elsa constantly. But it's not just girls and women, every time I see the Let It Go scene on youtube I want to lay my sword at her feet and swear my fealty to her.
We don't even know much about Elsa. We know the tragedy of her life and the sadness and fear it brings. I'm loathe to suggest a sequel to a Disney classic but I'd love to learn more about her.