Not much of a Christmas present, I know, but I've got half an hour, and there's a distinct possibility I've had too much to drink, so while this entry is significantly less refined than previous, I won't even request that you take it with a grain of salt due to the circumstances. After all, the first thought is just something I've noticed now re-watching Batman, and the second is an idea that's been kicking around in my head for a few weeks.
1. Stairs seem to be a rather crucial motif in the first Batman film. Consider, for instance, the gunfight at Axis Chemicals at the beginning. Napier keeps climbing higher and higher, only to fall that much farther when he's scarred and disoriented I(symbolic of his rise to power, maybe?). There's also the odd, though clearly intentional, parallel of the "after dinner" segment of Vicki Vale's date with Bruce Wayne and her eventual abduction by the Joker, him leading her up the stairs of the cathedral. In the first case, she's clearly on the offensive, actively pursuing Wayne, just shy of outright seducing him. In the second instance, the roles are reversed and given a distinctly darker twist, and with Bruce replaced by the Joker, previously shown to be clearly obsessed with Vicki. One could probably write a book or two on the gender-role subtext of this motif, but it makes for a far more interesting meditation on the notion and dangers of obsession.
2. I won't go into it full-force here, but my biggest problem with The Dark Knight is that the overall plot feels like it's a string of loosely-connected vignettes whose only common thread is that they're all schemes by the Joker to cause chaos. Granted, that's the idea, and there's obviously still plenty to like in the film in spite of this, but cohesiveness is an essential strength to any movie, regardless of the volumes of established lore behind its source material.
Put simply, if I were in charge of making The Dark Knight, entailing that I'd have to tackle getting The Clown Prince of Crime onto the big screen with all the menace he's thus far conveyed on the small screen and comic book page, I would essentially reduce the Joker to his core concept and spread it as thinly as I could. In essence, I'd take a cue from Batman Beyond and make the Joker a "Gang" of sorts. Actually, it would be more a "successive collection," but in a more abstract sense than something literal like the film Fallen where a consciousness is transferred physically from person to person.
The pitch, in a nutshell, is thus: by the time the film opens, the Joker is already either dead and buried, or incarcerated with absolutely no chance of escape. However, the whole rest of the film would boil down to Batman dealing with copycats, all very different from one another in terms of M.O.s and patterns, but all sporting the same makeup and reckless abandon for life and morality. The resolution of Batman's character arc would therefore be the realization that he will never truly defeat his longtime foe or crime in general for that matter. Of course, he'll decide to fight in spite of the attrition, but the agony could still surely be felt.
To put it in another and even smaller nutshell: I'd have multiple actors playing the Joker.
If the whole notion sounds silly and far-fetched to the point of completely straying from the path, it really isn't. The concept of a "foe of many faces" has been done before; the villain known as The Red Hood historically was comprised of only one Real McCoy, with a series of copycats following thereafter, the Joker and even a former Robin ironically among them.