Except that every princess film except 'Brave' requires that the heroine end up with a male. Personally, it was refreshing to see a princess who didn't need or end up with a man, a message that runs counter to girls' ideas about romance and love (i.e. Twilight). No woman needs a man, and every princess film prior to 'Brave' exalted the idea that women can't find happiness without romance, love, or their Prince Charming. That is the tired princess storyline. I don't recall any princess films like 'Brave' where the heroine wielded a bow and arrows and still ended up with a man.
I don't think Merida's resistance to being a 'girly-girl' was so much that she hated it, it's because it wasn't what she wanted. Her mother forced it on her. I'm a cross between a tomboy and a girly-girl: which one I am depends on the day. I don't find 'Brave''s message condescending or demeaning the role of a woman; if anything, I found it rather empowering, as I found the role of Katniss to be empowering.
your half right Princess Movies fall into 2 categories (we'll use Disney films are they are more plentiful).
You have Princess Classic: She's passive, sweet, domesticated and typically not very developed as a Character (either due to source material or the film itself). She is abused, or goes through something horrible typically has her fate set by outside forces (a Prince and evil character) and is wisked away without having anything resembling a character arc.
the second is Princess Power: She wants something. Freedom from an arranged marriage/overbearing parents/being an outcast/female's role in society----whatever it is. She goes on a trip finds out it's not as easy as previously thought meets a man who she isn't quite taken with ,but warms up to. She learns her responsibilities, and is rescued/rescues/works with the prince Character and has a happy ending typically in a Christian wedding.
While the Princess Power is an improvement over the Princess Classic, it hasn't introduced anything new since 'Mulan' in 1998. I would think to keep the Genre from getting stale the Princess must further evolve. I think Tangled hold a few new ideas in itself. The Princess goes out and makes a plan on her own (while this is present in 'Mulan' most other Power Princesses are thrust into their plot), saves her man, while still keeping the traditions of women---Kindness, Domestic work, and Material instinct. Also, there's this test I forget the name of in Hollywood, that judges if women characters are well developed and treated equally as men. The film must pass each of these:
1. you have 2 named females that appear more than once
2. They have a conversation between themselves, and themselves only
3. they have a conversation that isn't about men.
I'd find it interesting to see that taken to the Genre. Also, I think the Modern Princess movie has to take the Psychological aspects and relationships in stride. Cinderella (1950), has a great opening showing Cinderella with her father, and then her mourning at his deathbed. however the rest of the film Cinderella is overly patient, and overly sweet. She's about 18 , and her father died it appears around 7. So over 10 years your Mother has treated you cruelly, acted as if you were dirt, forced you to do the work of at least 3 people, while giving your own siblings everything. I'm sorry, I don't buy it. Cinderella is so vague her 'I want' song, is 'A Dream is a Wish your Heart Makes'.....what exactly does that mean??? The movies never explains. She also makes no effort to progress her story. Her dress for the ball is made for her, and then she is given a coach and gown , and then a prince. She doesn't even complain... EVER.
Now lets look at Cinderella III:A Twist in Time (we'll not look at that horrible disformed thing that's Cinderella II in the corner over there *tosses sheet over it*). So the film starts with Cindy as a Princess Classic, and then turns her story upside down by forcing her to work toward her goal starting with the shoe fitting. It's a great study on how to make a bland passive character into an interesting active one. While the film regrettably doesn't touch the Father/Mother dynamic that would realistically have a huge impact on her character, it does flesh out how she relates to everyone else, thinks and plans. She's not perfect, nor is she a super warrior , she more than once nearly gives up, and eagerly embraces her own femininity without sacrificing any of the qualities that have caused the Power Princess to grow old.
Dang, I've been typing longer than I thought I was....