4. Got what he wanted:- Well, who was the winner in the end? Undoubtedly, the JOKER. He wanted to prove a point that even the symbol of justice himself could turn into evil. And it did. Harvey Dent. Luckily, the Dark Knight took the blame on himself and somehow delayed the fact that Joker won. But for how long?
5. Laid out the platform for the destruction by Bane :- Jim Gordon had a report prepared on how Harvey and not Batman was responsible for the death of cops. But he hid it from the masses. When Bane got that report, he announced that since Harvey was himself a criminal, all the men he put behind the bars, have the complete right to freedom. The rest we know.
So, one must agree that the Nolan’s joker was no maniac, no psychopath. He was no freaky clown with creepy sidekicks, cheap fancy toys and magic cards. All he had was his manipulative conversations that turned every single situation in his how. And the way he executed every bit of it. Man!
DC needed a better class of criminal. And Nolan and Ledger, gave them one. ☺