>>714734153
I've read about the original concept myself and it's still not much better you're right.
Perhaps a way to rewrite her character while still keeping her as she is today is to simply have it be Kanako herself that uses the serum and Ceroba instead expresses extreme guilt that she couldn't be there to stop her.
Would mean that Ceroba still was neglectful but isn't dumbed down to the point she'd use her own daughter as a guinea pig.