Question(s) about Season Finale about Smallville. Could be a spoiler if you haven't seen it.?

Why did they kill off Jimmy Olsen? Isn't he a part of the Superman saga in the comic books? Why didn't they kill off Chloe? She isn't important to the story, at least from the comic book point-of-view. And did anybody else see her put her hands over her stomach after Clark walked away? Is she pregnant?