Making her a "bitch" kind of breaks what Nasu wanted to do from my point of view.
Honestly pulling stuff like this requires more nuance than Nasu works with most of the time. I can agree that she was badly executed but even if she was done better she'd probably still not be recieved well, because the way this is set up does not make her traditionally sympathetic. Which is why Nasu tried to tap deep into the abuse victim moe everyone loves.