Mulan is enjoyable enough, but as some of you have mentioned it's nowhere near as trans* friendly as some might think. In fact, I find it somewhat hostile.
It pained me to see another society very much like my own used to be, where to be born female meant that you were pretty much a servant of your father and then your husband. Did you see the way the other women treated her like a piece of meat at the beginning of the movie, when they're trying to beautify her? And the only way Mulan could escape her fate was by pretending to be a man. But did she actually escape it? Did she gain equal rights for herself, or better yet, for all Chinese women? No. She saved the emperor and he offered her emancipation, but instead she simply wanted to return home to domestic life with her father, and she gets married in the sequel. So the subtext was this: women have the skill and potential to be equal to men in theory, but really their highest aspiration is to become a wife & mother.
Did you also notice how dressing & behaving like a man is portrayed as 'just a phase' that she goes through out of necessity (because her father has no sons) before returning to her 'proper' role as a woman? That's not at all helpful to trans* people whose families insist that we're 'just going through a phase'. It delegitimises our experiences and makes it harder for our families to believe us.
In the original Chinese legend on which the movie was based, Mulan fights with the army for 12 years and her comrades-in-arms had no idea that she was female until she reveals herself at the end of the tale. And there's no mention of a love interest. This is how The Ballad of Mulan ends (according to Wikipedia):
The male rabbit is swifter of foot, The eyes of the female are somewhat smaller.
But when the two rabbits run side by side, How can you tell the female from the male?
That's a much better message than "OK little girl, you're lucky you got away with it for a while, but you really ought to get back home - the dishes need doing."
Still, at least it gives the general public the idea that gender boundaries are not concrete and can be crossed. That, at least, is something.