I should rephrase that: I think it sort of works for Batman while also taking some of the fun out (when a guy who wrote a million Batman comics couldn't think of why another character he wrote extensively shouldn't kill Joker, sounds like a problem). I remember the death of Jason where he's all mad but won't tell Clark or Gordon, and I'm not really sure why people roll with that. Superman would get peed on for swallowing such a loss.