Nikvoodoo: I would argue the Arena wasn't dealt with one chapter because it is still unresolved. The zombies are gathering there, presumably with a "plan" in place. The mallers efforts wouldn't have finished them off.

Likewise, I can see a chapter contained scenario with ground zero, but I don't think the broader story will benefit if all involved with ground zero is resolved in a single chapter. It will hold revelations to what led to the zombies/apocalypse. Though, as I'm writing this, I can see how ground zero can be used to shed some light into what caused the zombie apocalypse and then left alone with many unanswered questions. And this could easily fit in a single chapter. Fair enough.

Also, you're right, your commenting on Scratch effectively made my point.

Those mentioning zombie queen: what I like about this - can explain hive mind mentality of zombies a la bees. While Ink/caller zombie can "control" other zombies, that doesn't provide an answer why. A queen could produce hive-minded zombies. What I don't like about this - our current "official" understanding is that whatever changed everyone happened simultaneously around the world, meaning there are numerous queens that acted at the same time. It's not that a coherent story can't be created for this scenario, but implies the zombies are an their own "species", not converted humans. Also, it doesn't account well for the observation of "smarter in life, smarter in undeath".