Spider-Man: Miles Morales has me thinking about what would have happened in WB Montreal decided to make a Nightwing game set after Arkham City instead of the prequel Arkham Origins that ended up making.
There would be a surprisingly large amount of things that would remain the same. The plot of the 8 assassins could still work. Black Mask could still remain the main villain. And the winter aesthetic can just be reapplied to Bludhaven.
The probably the biggest change in this hypothetical scenario is that Black Mask wouldn’t turn out to be Joker in disguise. The Joker would not appear in this game at all for obvious reasons.
Also Deathstroke would likely receive a sizable upgrade in his role in the story. He would likely seize control over the manhunt for Nightwing much like Joker did in Origins only without the “Black Mask is actually me in disguise” part
It’s questionable whether Bane and Killer Croc would still be assassins. Copperhead, Deadshot, Firefly, Shiva, Electrocution and of course Deathstroke don’t have any canonical hang ups that prevent them from being in this game.
As for the other characters, Riddler, Penguin and Mad Hatter all have the same canonical question marks as to whether they could appear. Villains like Anarchy would fit right in though.
Given that Nightwing was tracking both Panguin and Croc in Knight, in retrospect you can easily transition those into tie-ins to Nightwing’s game and keep Croc & Cobblepot in the story.
Also while we’re on the subject of Croc. Blackgate’s role could be replaced with Iron Hieghts.
Obviously this isn’t exactly how the game would have gone had they gone that route over a prequel but it’s interesting to consider.