Well it's not that people really hate her, but compared to the rest of the cast in this show, she does act a bit like a real bitch most of the time. And you have to understand that her change of attitude towards the end happened so fast that watchers simply ''didn't buy it''. And now when she is not in the center of attention, it will give some time for other characters to shine, which I think people look forward the most.
And don't get me wrong, even with 100% tsun in her soul, I would still want Kirino as my sister.
