for nice:
sakura, orihime, elder god demonbane, kaya, vivi
for evil: kid boo, mayuri, hidan, hades, freeza
you cant really put any well intentioned extremists in the "most evil" slot. because even if your deluded you still have some type of noble intention. the people i listed...no.
if rin was nice she would gave obito a chance.
how was she meant to know he liked her that way?
he is between evil and good though. fits in neither category
Aizen simply didn't have any hidden morals to his actions; he wanted to be powerful just to be powerful at the expense of human life.
no he is sort of well intentioned in that he hates the soul king and doesnt want to be its slave. he hates that uruhara is subserviant when he should rebel.