Also I doubt Batman dies. All the Arkham gamed have a free roam and side missions after the story, and the game would feel odd if after the main story you couldn't go around and do stuff and enjoy the batmobile more.
But one day some gentlemen will create the best hero ever, he will show the greatness of humanity and would beat that sorry abomination Superman, he will be a better example of an actual art form and would top everything else.
He will be the main example of what every gentleman should be and will be with a plan and will be better for ever and ever.
He will use a red costume, have blonde hair and have vampire wings.