Re: The Joker sized elephant in the room
If Ledger were still alive, I could see Joker serving as the judge, just because he targeted Dent in TDK and because one of his stories about his past involved his wife getting involved with the mob. The scene could've elaborated more on Joker's past through the sentences he passed on the upperclass rich--businessmen and elected officials who were tied with the mob--and progressed Bane's plan for Gotham.
"I defeated your uncle Victarion and his Iron Fleet off Fair Isle, the first time your father crowned himself. I held Storm's End against the power of the Reach for a year, and took Dragonstone from the Targaryens. I smashed Mance Rayder at the Wall, though he had twenty times my numbers. Tell me, turncloak, what battles has the Bastard of Bolton ever won that I should fear him?" - Stannis Baratheon