I've watched this probably 10 times with my daughter, and every time I notice some piece of the plot that takes me deeper into understanding this story. It really is brilliant, a warning about the dangers of arrogance, of balancing the good of the individual and the good of the whole community. I never really "got" the mother's perspective until the last couple times I watched it - I just thought of her as trying to hold her daughter down, but she has her own good motivations rooted in a deep understanding of her culture's legends.
A couple critiques: Merida's central struggle with her mother is about choosing a man to marry. I look forward to the time when four-year-old girls don't have to think about their relationship to romantic love. There are plenty of other mechanisms that could have suited this purpose (choosing a role in the community, for example). The Moana storyline handled this extremely well.
Finally, there are no models for positive masculinity in this movie, which is a shame. A feminine hero doesn't require the context of clumsy masculinity. This is harmful to our current masculine culture, which can use all the help it can get. I feel bad for the boys who watch this movie, and I hope for something more balanced in the future.