Sorry, I have to admit, first off, I'm not a fan of any of the super-hero genre. But whenever I read, as I did here, the comparison with male characters: i.e. Diana's outfits are revealing, while the men remain covered up. It just makes me wonder, isn't it possible the male characters are wrong? Didn't Celts fight entirely naked? Scots wore kilts to battle as late as WWI. Roman legions, Greek hoplites, etc. mostly fought without being entirely covered.
Granted, from what I know of Wonder Woman, she was designed to be appealing. I can't really say if the latest versions of Batman and lord knows which other male characters appeal to women, but if they were costumed with sex appeal in mind, would that be wrong?