The "definition" of a hero was posted above. I don't see how your feeling that Gollum's world was torn apart and so on makes him eligible for the Title of hero. The fact the society labels people as hero's when they did not intend it to be that way is redundant. Society judges people to be many things that they are not. You can't just go around handing out hero sign's to everyone who has had a bad day. I wonder why you would say that above all Gollum wanted to make sure Sauron did not get the ring. The whole premis of Gollums personality is that he is obsessed with obtaining the ring for himself. He served Frodo for that purpose, and he tried to kill him for the same reason.