Can anyone say romantic betrayal? Link falls in love with said villain, is manipulated, makes some bad choices, dark epiphany when plans finally come to light, etc, etc?
Meeeeh, good idea, just not suitable for a Zelda game.
Really, I don't want a female Villain. Remember Veran? She struck me as more of a ***** than evil villain. The problem with female villains is that they're usually made out to be *****y sex symbols. Veran was like WA-BAM! with the hips and the tits. Imagine if that was in 3D. I know it'd be visually appealing, but that doesn't need to be in Zelda. Unless they can pull of making a female villain somebody who's character is well developed, then I don't want one. With ugly men like Ganondorf, they tend to focus on the character's background more.
This is the case with most game villains. Even the most deranged, effed-up female villains end up being nothing more than eye candy in the end, and I don't want that in my Zelda. I want Nintendo to blow me away again. Not saying she shouldn't be a hottie if there was a female villain, but I really do want there to be a lot of focus on the character and her reasons for being the antagonist.