Now I'm a fan of Jack's Joker. But in terms of over all feel, Heath's Joker is in my eyes, and many that see it darker then Jack's Joker. Yea in context if you explain what Jack's Joker does verbally and explain a scene, it sounds dark, and it is. But honestly even when I was 7 years old and saw the film, I was never scared of the Joker.
The Jack Napier thing as regwec did say took away from some of the "creepiness" of the Joker. Though I still love his preformance, and it was well done, but I saw it well done for the time, and for the time when Comic Book movies were not taken that seriously by anyone. B89 is still a classic, and Jack rocked the house. But reading that article on CNN, I do think Ang Lee put it best, it seems even a lot of the famous Batman writers creaters like Dini and so forth and even Mark, comment on from the trailer alone how "dark" feeling Heath's Joker is.
I love Jack's Joker, but I still always just see Jack in white makeup. With Heath, it is like he transformed himself to the Joker himself. Though Joker in B89 did horrible acts, and was very violent, it never...felt scary, or threatening even when I was a kid. But even now as an adult, looking at the Joker in the trailer alone, it gives me the chills, he is darker in certain ways, not just context, but the way he moves, talks, and looks, not even just physically, but that aurora that Heath gives off, and the look in his eyes.
I agree, in Batman '89 it was still always Nicholson as the Joker. In this it does look like Heath 'becomes' the Joker. When that trailer hit not to mention some of those later Joker pics...I couldn't tell it was Heath under there.
Both Jokers will always be great, but I think there is nothing wrong with getting excited for Heath's Joker, because even from a Trailer, fans, general audience and many professionals alike are praising from what they have seen. I'm stoked to see this performance.