[@TheWindel]

The latter. Now I don't disagree with having the villain kill magical girls; it sets her up as a menacing character just fine, and if the victims were unrelated to anyone we could recognize I wouldn't have had any problems with it. But like this, she's portrayed as being better and more powerful than the canon cast, which reeks of wish-fulfillment, power fantasy, and being a [url=http://tvtropes.org/pmwiki/pmwiki.php/Main/VillainSue]Villain Sue[/url]. As an AU, this RP shouldn't have canon characters included in the story itself. It breaks the immersion.
Also, Sayaka's or any other canon character's power levels shouldn't be compared to the characters in this RP; it's irrelevant.