If there’s one good thing about superhero stories dominating mainstream media, it’s that journalists have gotten much savvier about covering the deaths of prominent superheroes as publicity stunts, rather than as massive cultural milestones. DC Comics’ 1992 “Death of Superman” arc got such widespread mass-media attention that it launched a fad for killing off major legacy heroes — who inevitably returned in one way or another once the novelty wore off. Meanwhile, longtime comics fans mostly snickered, knowing full well that superheroes rarely stay dead for long. Usually, killing a hero is just another gimmick to sell comics, goose sales, and shake up the status quo — so the 13-episode first half of Young Justice’s fourth season has been a compelling change of pace.