Onomatopoeia
A prominent theme in the game is Batman’s struggle to allow others to take part in his crusade. By the end, he severs ties with his allies to protect them. It would be interesting to see a mission that played with these themes. A perfect one would be a villain created by film director and podcaster Kevin Smith during his run on Green Arrow and Batman called Onomatopoeia. He is a formidable serial killer that targets and makes trophies out of non-superpowered vigilantes with brutal precision. Onomatopoeia is an expert in strategy, combat, and firearms – and he is not above hiring desperate thugs and militia members to do his bidding for him.
He is called Onomatopoeia because he never actually speaks; the only words to come out of his mouth are words emulating the sounds around him. This weird quirk coupled with the fact that no one truly knows anything (even Batman) about his past, identity, or what he looks like makes him an oddly terrifying character.
If Onomatopoeia were to have a Most Wanted mission, it could involve Batman discovering that each and every one of his allies is being systematically targeted (or he finds them dead, but as part of a red herring) ending in a final showdown. His mission would be even more disturbing if Arkham Knight would adapt the Kevin Smith’s The Widening Gyre in which Batman solves crimes & partners up with the vigilante Baphomet (being Onomatopoeia in disguise after their first encounter) and at the last moment reveals himself with a knife at the throat of one of Batman’s allies.