Yeah, well, I could live with it. I'd still prefer no origin at all actually, but I could live with The Joker's origin being connected to Crane's experiments.
I'll go ahead and tell you all of what he said.
According to this source the basic plot of TDK will be Batman teaming up with Dent and Gordon to track down The Joker, who is on a murder spree, knocking off different individuals of importance. Meawhile they are also taking on the mob, meaning Maroni and his henchman. I got the impression from the guy that Sionis will be an associate of Maroni's, somewhow. Penguin will be in as another mobster. Rachel isn't in it, but shes not dead, her absence is explained(he didn't say how). Near the end The Joker is brought down, and sent to the newly re-opened maximum security Arkham Asylum, ran by Dr. Harleen Quinzel. Maroni goes on trial(guy didn't say for what) and during the precedings Sionis scars Dent. The movie ends with Dent waking up in a hospital bandaged up, hearing people screaming at him(hes finally snapped) and he goes berserk, the nurses and doctors rush to his room but when they get there they find it wrecked and Dent gone, the window left open, ala BTAS. A cliffhanger ending.
He also had a somewhat more vague idea on what they were doing with the third film, saying that Two-Face would go to war against Maroni(who apparently beats the charges), a freaks vs. the mob storyline kind of like TLH. Also in the second half the film things get worse when Dr. Quinzel unleashes The Joker again.
EDIT: Another thing he mentioned, Loeb will be Joker's final victim in TDK, and because of it Gordon will be the Commisioner in the third film.