“…The link you showed me was far from revealing. From your link I thought I was expecting: bikinis, ankle high heels, short shorts that shows a person’s behind, and somehow reveal lots of breasts. You know, half naked clothing.”
She concludes that women shouldn’t be judged by wearing revealing clothing:
“Showing a bit of skin is natural and shouldn’t be seen as something ‘sexy’ or demeaning. Society demonizes women’s bodies and makes us want to be ashamed of expressing our bodies, for ourselves not anyone else.”
And I agree with Nadia on both counts: the costumes that I linked to were mildly pornulated at best, and they were not nearly as bad as the outfits typically associated with mainstream pornography.
But with a major Hat Tip to Twisty, I still believe that they are a big problem, even for women who want to express their bodies through these costumes.
First, while these outfits are not as bad as those in mainstream pornography, they still fall well within the pornographic aesthetic. A pornographic outfit is not defined by the length of the heel, the height of the skirt, or the plunge of the neckline. They are defined by the traditional aesthetics of their design, and the connotations that they imply. For example, stilettos are not hugely pornographic by themselves , but “stilettos in bed” is deeply rooted in pornographic symbolism. Even though the adult women’s Halloween costumes use more fabric than those found in a typical pin-up calendar, they still allude to the traditional tutu-and-bodice / french-maid-cheesecake aesthetic that is deeply rooted in pornography.
Hell, many of the costumes, like the Lust Fairy, the Burlesque Showgirl, the French Maid, the Bad Kitty, the Bombshell Bunny, the literal Pin-Up Sailor, and the friggin entire genre of schoolgirl outfits, are direct rip-offs of pornographic stereotypes.
That said, I do not believe that women who wear these costumes have intentionally degraded themselves into pornographic sex objects. But I do believe that the majority of women’s Halloween costumes were designed by, and created for an audience acclimated to, a culture of pornsick patriarchal oppression. A culture that defines women not by any terms that they wish for themselves, but only in terms of the Male Gaze: male desire, male fantasy, and female weakness in the face of male power. 
As an example of this, just take a look at the “adult women’s” Darth Vader costume:
All power, fear, darkness, and authority of the character has been removed from this costume. It is a sexist, hypersexualized mockery of the original character, that says (along with many of the other women’s costumes on the site): “I’m a chick first, and everything else second.” 
And don’t get me started on the adult women’s Teenage Mutant Ninja Turtles outfit:
It’s not a matter of pride or demonization of women’s bodies. It’s a matter of circumscribing the expression of women, and their bodies, to the tired tropes of pornography and sexual objectification.
But even beyond that, since all these costumes rigidly adhere to the cheesecake aesthetic (short skirts, bodices, stilettos, with very few exceptions) there is little room for actual creative expression. Many of the fantastic characters that these costumes are based off of (like Darth Vader) become lost when crammed into the old cheesecake trope.
But this is all squarely the fault of a Patriarchal society that demands that women on Halloween be dressed as chicks first, and anything else second.