Originally Posted by HisMagicTrick
Yes I was actually thinking about this. I mean, I really hope there will be some mention of the Joker, but if Ras Al Gul wasn't brought up in TDK then there's a chance the Joker won't be in this one. But, as others have said, because Harvey will be spoken about in TDKR then maybe the Joker will.
The main difference between the lack of mention of Ra's and a potential lack of mention of the Joker is that the public are unaware that Ra's and the League of Shadows were behind the fear toxin attack. The viral for The Dark Knight made it clear that the people of Gotham believe that Scarecrow and an unknown Terrorist group were responsible.
The Joker made himself a well known, self publicised force within the city and threatened the populace on television, walked the streets shooting at cars, blew up a hospital (after telling everyone in Gotham that he would) and forced an evacuation.