Actually, the worst case scenario for Quinn wasn't death either for me, even if I think she will die by the end, but I could seriously see her, down her path, having serious remorses about her misdoings, obviously with the help of the MC... but while trying awkwardly to fix her shit, she will get people killed as collaterals, and I've been suspecting Riona (who the hell would hate that girl, honestly ?! yeah she's broken as hell, but she's sweet and just misled) to be a victim in the end since the last 2 years. While trying to do good, Quinn will fuck this up and still manage to do evil without intentions. That would be the twist, live by the sword, die by the sword, even if you put the sword down in the first place.
And yes, she will be hated. But everyone will remember her, like they remember Leah from AL.
Good games is where you have fun, great games is where you build memories, good or bad.
(one of my 'doom scenarios', just a theory, of course)