He wasn't as controlled as Lecter, as I stated previously.
I really don't like comparing one of the greatest (yet fictitous) psychotic minds to a comic-gone-film villain. Lecter was on a level 500 times larger than Joker. Smarter, scarier, more ferocious, and let's face it, funnier. I'm not knocking Ledger's performance, but there's a reason why Anthony Hopkins is called "Sir".
But, more to the point. Lecter was all about control and stability. He wanted harmony and perfection. The Joker is the absolute opposite. Smart, but chaotic. Psychoanalytical, but puts it to use creating monsters and sowing mayhem. Lecter killed a musician because he made the orchestra sound bad and thought it'd be fun to feed him to the symphony's board to make up for his shortcomings. The joker makes a pencil disappear and ultimately doesn't succeed with his final bang. Big whoop...
Let's please try to refrain from comparing my all-time favorite anti-hero, Hannibal Lecter with a mediocre comic villain, like the Joker. They ARE NOT comparable.