Cho isn't a main character. SHe is one of those characters that is used to add to the books feeling ya kno.
JK made her to show that Harry is growing up and is starting to feel differently towards girls. I am certain that Cho will not be on of the characters that is killed in book 7 because she wouldn't have that great of an impact in t he plot and she is not a main character.

As for hating her-I don't because it wasn't her fault she cried a lot, I mean, her old boyfriend was just murdered and she is a little sensitive. So what, that is no reason to hate her!