My personal opinion (coming from a 20 year old Brit) is that the "princesses" and their respective films reflect the world that they were brought into. As you may or may not know, fairy-tales mostly originated from the oral tradition, being passed down from generation to generation before being written down by authors such as Charles Perrault (
Cinderella, Puss in Boots etc), the Brothers Grimm (
Hansel and Gretel, Snow White, Rapunzel etc) and Hans Christian Andersen (
The Ugly Duckling, The Princess and the Pea, Thumbelina etc). As these authors captured down these folk-tales and recounts of the supernatural, they infused a part of their culture, society and self into them.
Bluebeard, a story by Charles Perrault, has references to buying aristocratic titles (which occurred in France a lot in Perrault's day).
Hansel and Gretel and others were edited to reflect more the Grimms' protestant and Germanic values (e.g. evil birth-mothers turned to evil stepmothers) and they ended up collecting retellings of Perrault's stories that had re-entered folklore (
Little Red Riding Hood and
Sleeping Beauty, for example). Meanwhile, Hans Christian Andersen took fragments from folklore and pretty much wrote new stories altogether, many with an autobiographical nature (
The Ugly Duckling is a barnyard recreation of his rise to fame,
The Little Mermaid is said to be a story about his repressed homosexual love for his best friend).
Likewise, Disney, when adapting such classics, has infused a spirit of the era and North American values into the traditional stories. A lot of the heroines seemed to have been influenced by popular actresses and pop-stars of the era they were made in. Snow White is hardly an independent figure.
Cinderella, released in 1950, has a somewhat more independent heroine, and
Sleeping Beauty from 1959 has a heroine even more independent, though at the end of the day, both Cindy and Sleepy still rely on men; essentially, there's hints that emancipation is starting to appear, but it's not that big yet. By the time that
The Little Mermaid, Beauty and the Beast etc appear, we can see that a lot has changed, as the heroines, although still somewhat anchored in romantic fairy-lore, have characters with a brain and a strong determination. Andersen's mermaid was a drippy waif, whereas she resembles a spunky teenager in Disney's version; they are both naive, but Disney makes a more accessible heroine.
As well, look at critical studies on Disney's use of fairy-tales. These links given here could be of use (this is from a site on the subject of fairy-tales):
http://surlalunefairytales.com/introduc ... tales.html
Also, what could be useful is to look at the original source materials. On that same site, there are annotated versions of the original, variants throughout folklore, illustrations by golden-age illustrators such Arthur Rackham and a gallery of modern interpretations. I'll give you links to the tales that Disney adapted:
http://surlalunefairytales.com/beautybeast/index.html
http://surlalunefairytales.com/cinderella/index.html
http://surlalunefairytales.com/littlemermaid/index.html
http://surlalunefairytales.com/sleeping ... index.html
http://surlalunefairytales.com/sevendwarfs/index.html
I'd also recommend looking (even just briefly) at other films with important female characters, such as
Alice in Wonderland, Enchanted and
Peter Pan. The women in Neverland, who range from around twelve to early twenties, all have a sexuality and love for Peter Pan of sorts (in particular Tinkerbell, who is completely infatuated with Peter). Alice, although a younger girl and not having any romantic interest, is a fairly strong character and compared to, say Cinderella, can stand up for herself or get cross like any normal girl would. And
Enchanted is essentially a nostalgic/tongue-in-cheek commentary on Disney fairy-tales...