User blog comment:Gammabomb/The Dark Knight Rises needed Joker/@comment-246292-20120819222257/@comment-4567023-20120820143945

When Selina was marched into Blackgate, there was someone holding a playing card through a cell door, but we never see who. From a plot point of view, it would be near-impossible for Joker to not make a move if he had been in Blackgate. But it also looked very likely that he would be "shot while trying to escape" at the end of Dark Knight, ie summarily executed. It did seem a little ambiguous. But I agree that replacing Heath would have been a big mistake.