3. The Supervillains Before The Bat
In tons of Batman stories showcasing his early years, including Year One, the order of events goes 1) Gotham is riddled with Mafia crime and corrupt police, 2) Batman appears and defeats organised crime, 3) in the absence of organised crime, the costumed supervillains rise. This has implications on Batman's status as a hero. The idea can go: well, if Batman weren't around, we wouldn't have psychos like the Joker running around would we? The Mafia are preferable to a maniac who tries to poison the Gotham reservoir, any day of the week! This can reflect on Batman badly as it makes it seem like Batman has inadvertently caused the crime in Gotham not just to rise but to become more deadly. In Zero Year, we see that the supervillains are around before Bruce becomes Batman. The Red Hood Gang, the Riddler, these threats are present before Batman appears making him a reaction to the supervillain threat than a catalyst to creating them. This shifts the scales on the perceptions on Batman and makes him more heroic as a result. It's an inspired approach by Snyder and one that I feel should become canon because it's so right.