When we last left off with Superman in Batman v Superman: Dawn of Justice, he had sacrificed his life to defeat Doomsday, though it was foreshadowed minutes later that the death would not stick, as is the norm in comic book stories. Sure enough, the Man of Steel will somehow be resurrected in Justice League, and perhaps the events of that movie could lay the groundwork for the tonal shift Matthew Vaughn wants in in Man of Steel 2. Superman clearly struggled with being Earth's protector in Batman v Superman due to the public's mixed reception to his existence, many seeing him as a benevolent god-like figure, others seeing him as a menace. However, with Justice League leaning more heavily into Superman having been a beacon of hope, his rebirth will hopefully draw more people to support him as a hero when Man of Steel 2 rolls around, thus producing a more positive atmosphere.