In theory, Judge Dredd: Day of Chaos should be everything I hate about big event comics. It goes out of its way to be grim and dark even by Dredd standards, boasting a body count over 300 million, features a protagonist who's often powerless to stop the terrible things that are going on, and the only person who really comes out of it with anything that remotely resembles a victory is a mass murderer. It's almost thoroughly devoid of hope, with a focus on brutality and horror that's telegraphed from the opening. Half of it's built like a zombie story, and in true 21st century event comic fashion, there's even a dude who gets his arm cut off.
Taken all together, that's essentially a checklist of things I never want to see again in superhero comics. In Day of Chaos, however, that all comes together to form a textbook example of how to do event comics right.