I kinda wanna play devil's advocate here. ^^ Sure, it's all fine and good to just "design what you like", but keep in mind that when it comes to what people "like" about female characters, interests tend to converge, if you know what I mean. 9_9
People who ask for female warriors who don't wear bathing suits into battle aren't always accusing character designers of sexism or demanding that they deny their own wishes. I think a lot of the time, they just want a little diversity in what "likable female" can look like. "I like women" and "I like women in miniskirts" shouldn't mean the same thing, y'know? Women who *gasp * don't wear miniskirts do exist...
I mean, what's led to some of the most harmful stereotypes in the entertainment industry today? Things like "main characters should be white supermodels" and all the ridiculous ideas they spawn? Most of it isn't the fault of evil racists and sexists; most of it comes from people just following their preferences based on things they've seen before...which leads to future generations following those same preferences, based on things THEY'VE seen before.
And eventually you end up with 'unspoken rules' in the industry. Like, no one says explicitly that a woman who isn't conventionally attractive can't be the star of a franchise...but how many franchises do you know of that even come close to breaking that unspoken rule? Heck, even "Ugly Betty" was cute as a button, to be perfectly honest.
What am I trying to say here...I guess, like ethnic background and personality type, wardrobe is another type of character diversity that I don't think should go totally ignored. If nothing else, imagine all the girls out there who won't have to suddenly get half-naked in order to cosplay their favorite characters. ^^;