6. The Joker Conundrum
The Problem Arguably the greatest criminal in Gotham's history somehow conspired to disappear entirely for the events of the final film in the series, despite his supposed love of chaos and crime - failing to take advantage of a unique situation inside Gotham to create his own art. This was also despite the fact that he had pretty much been handed a get out of jail free card by Bane's opening of the prisons, and Arkham Asylum (since Dr Crane was freed). So where was the clown prince of crime? Had he somehow just walked away, convinced that with Batman gone he had no fitting adversary? Had he used Batman's secret entrance into the city to evade the probably eagle-eyed attentions of America's police force and army as they stood on the very limits of the city? Or did he just decide he wanted to stay in Arkham? It seems odd that all of the other villains of Nolan's trilogy were in some way referenced in the finale, but the Joker was just allowed to become the maniacally grinning elephant in the room. Yes, it might have been difficult to make any reference without Heath Ledger, but unfortunately, as it was there was an all-too-noticable Joker-shaped hole in the film.
How To Fix It The Joker could very easily have been included in the film without the need to use stock footage of Ledger, which would have been a mistake, or even re-casting him - after all, Chris Nolan is supposed to be an artist. There is absolutely no reason why the Joker couldn't have announced his presence without actually appearing on screen. He could have escaped when Batman initially left his duties in Gotham, or even at some other point - and his empty cell could easily have been dressed to announce his former presence without him even needing to be onscreen or spoken of, which would fit with his tendency to escape Arkham in the comics. Alternatively, his continued incarceration could have been alluded to in conversation, since Talia and Bane would presumably have been aware and wary of such a wildcard. Either way, he could have been included to pay homage to the character's importance to the trilogy.