Batman has been in need of a great unburdening. It became necessary after Christopher Nolan's trilogy posited the Caped Crusader as a hulking avatar of turn-of-the-millennium anxiety. And it grew even more urgent after the drudgery of Batman v. Superman: Dawn of Justice, which was like chasing the heaviest meal of your life with a fully loaded, twice-baked potato. Over the last 50 years, Batman has crossed the spectrum from the campy, freewheeling POW! of the 1966 TV version to a grim-faced, gravel-voiced bulwark against festering corruption, urban blight, and existential malaise.