umm Batman is/Has been dark for most of his existence. It was only the 60s TV Series and a couple of decades of comics where he wasn't. Happy batman does not translate well. He is dark due to all the loss he has encountered in life. He is not a symbol of hope, he is a symbol of vengeance. In fact if we look at the big DC players as the Greek Gods, Batman is Hades (vs Flash as Hermes, Supes as Zeus, Aquaman as Poseiden, Wonderwoman as Hera, Green Lantern as Hephaestus)