As weird as it sounds, characters' deaths are one of the things that make HP good. Without them, the story has no sense of intensity or emotion. How frightful an evil overlord would Voldemort be if he didn't kill anybody? They'd have no reason to fear him, and just let him laugh maniacally while they went about their lives. Every book would read like a teen-crush fanfic that's hundreds of pages long.

I could go on, but I think you get the point-- deaths are necessary in lots of stories to make them forceful.

__________________