Here’s what I’d want:
Arkham series: Fleshing out the backstories of villains. Each episode akin to the Joker movie, building them up for the sequel.
Penguin series: Showing Oz’s rise to power and moral descent, building him up for the final film where he plays a key role.
Sequel:
-Bruce investigates the mystery of Hush, only to discover that the man under the bandages is not Nashton/Elliot as suspected, but Bruce Wayne, and tragically Gordon has him thrown in Arkham.
-A deep dive into Bruce’s neglect of his own mental illness (Think Black Swan, Birdman , Joker etc) and lack of healthy communication/openness (like how he never tells Gordon anything about himself).
-Gordon figures out that Hush was Clayface (an actor using deepfake technology or something, hired by Joker or Strange), and together with Catwoman help break out Bruce before he’s to be euthanised.
Threequel:
-All about the fear of loss, fear of loss of control, and grey morality (think Prisoners) with Freeze trying to save his wife, but killing only criminals to do so (going after the Court of Owls, who he works for as their lead cryogenics scientist). Maybe Bruce sympathises and contemplates letting Freeze do what he has to do, with the seemingly ubiquitous nature of the Court feeding into Bruce’s paranoia of the safety of his new family of Selina, Alfred, and young Dick Grayson (whose origins are tied to the Court).
-Bruce ends up bending his rules, coming to Penguin and the mob (and/or the Arkham inmates) for aid in an all out war against the Court, but in the end decides to turn himself into the police for what he did (also penance for his father turning to Falcone).
-Bruce learns to let go by letting Gotham and his family continue on without his protection/control, agreeing to let Alfred train Dick and take over as he serves time.