Originally Posted by The Joker
I used to feel the way you do about the lack of a Joker reference, Shadowboxer. But given it wasn't done out of sloppy writing where the script just clean neglected to mention him, and it was a conscious decision by Nolan out of respect for Ledger's memory, I am fine with it.
If anything else the legacy of his actions ripple through the movie. We know who destroyed Harvey. We know who killed Rachel. We know who's responsible for Bruce's mental state.
Lack of a Gotham POV is more of an issue than the Joker not being mentioned.