I think there'd be just as much outrage if they'd killed off any of the main male characters associated with the legend. The problem gets compounded, though, when you only have two regular female characters to begin with and you kill one of them off, and then have a replacement lined up immediately. It sort of perpetuates the perception that female characters aren't as important and essentially interchangeable, in that it becomes less about who the character is and more about having a token woman on the cast.