Yes comic book and recent literary properties are often more sacrosanct to the fanbase compared to fairy tales and myths passed down from centuries ago, but I'm asking a two-pronged question here. First of all, is there a reason that conventional wisdom demands that comic and literary properties based on boy-centric stories must be slavishly faithful while stereo-typically female-centric properties can be changed at whim to suit a more action-hungry (read- stereo-typically boy) dynamic? Even Twilight almost went that route, as the original film version constructed over at Paramount basically turned Edward Cullen into a Blade-type vampire killer before they put the project in turnaround and Summit Entertainment snapped up the rights and made a more faithful adaptation. We'd never think of altering Wolverine in a fundamental fashion, but Halle Berry is allowed/encouraged to screw up Catwoman however she sees fit. Moreover, both the concept of these changes and the end-result points to something more insidious. Snow White dons a suit of armor and charges into battle, and it's supposed to be read as 'progressive' or 'empowering'. Yet would we be just as impressed if James Bond put down his PPK and tried to 'talk it out' with his enemies?
The meme is the same: Female characters engaging in stereo-typically male activities (playing sports, killing people, etc) is seen as culturally progressive and/or 'empowering'. Yet male characters engaging in stereo-typically female activities is not only not 'empowering' but often viewed in a mocking light (see the Dudes Club in What To Expect When You're Expecting and/or any number of television episodes where the male hero finds a baby and has to raise it for 44 whole minutes). It should be noted that (spoiler...) Snow White and the Huntsman ends without having Snow White choose either of the two would-be love interests that are presented to her. Yet while it is a refreshing turn of events, it is implicitly saying that she is only a progressive woman because she killed and conquered and didn't get a guy in the end. It is not only that she engaged in 'guy behavior' but that she renounced 'female behavior' that makes her a strong female character in the eyes of the film, and perhaps certain segments of society as well.
At the heart of this concept, and the reason why Pixar's Brave (judging by its marketing) isn't nearly as feminist as it might want to be, is the false dichotomy behind the cliched 'girls can do anything boys can do too' meme. It sells the idea that male activities are inherently superior to female activities. We all cheer when Katniss Everdeen kills people but boo when Bella Swan aggressively pursues a guy. We scream 'empowered!' when Lisbeth Salander uses violence to save the proverbial day yet think less of her when she changes her appearance and uses her more conventional attractiveness to entrap a villain. And since there is no opposite concept in play, no societal pressures for boys to engage in 'female behavior', the message is that male behavior is inherently superior. We live in a society where having Snow White don a suit of armor is progressive, but Superman donning a dress is unfathomable. What message is that really sending?