There's nothing wrong with gender-bending. People can cosplay as they see fit. If their reason to gender-bend is to make a sexy costume, that's their choice. If it's because all of the female characters in a show/game/movie are lame and the men are dominant figures, that's fine if they want to transform them. It's not our place to judge a person on how they wish to cosplay.
I plan to do a femme-version with a costume group that we're working on for a few reasons: 1. I am not an 8 year old boy. 2. I don't have the body of an 8 year old boy. 3. I can only bind so much before it really becomes painful, and I still have chesticles. 4. I think my idea will be very true to the character, and cute at the same time.
I'm not doing it in order to "slut up" an outfit. It's for me, my enjoyment, and my comfort. People will still be able to clearly recognize the character, but it won't be done in a manner to make it intentionally full of skin. When done well, gender-bending can be fantastic: http://www.cosplay.com/photo/2810140/