Wanna change something that's so good All my love was all it took
(Continued past...)
She was angry that night. Kagome loved Inuyasha the way he was, yet Kikyo wanted him to be human and then she wanted him dead, never like he was.
It was her power and her love that got him to where he was.
Why change something that was so good?
In the end, he didn't have to, Kikyo was half-demon now, and that's all it took.