you would probably need to ignore a large majority of batman history in order for this to be true. joker has been trying to kill batman since their very first meeting in batman #1. you reference killing joke and yet you conveniently ignore the parts in that book where joker is SHOOTING at him and trying to STAB him.
i'm sure the character has evolved over the years, and it makes sense that after years and years of being each other's rivals that their relationship would take a bizarre yet more personal turn... but a joker that doesn't wish to see batman dead? that sounds perverse to me and another example of trying to fix what isn't broken.
and in the context of TDK, results in the movie having much lower stakes.
naw, i dont need to ignore it, you need to revisit it....the joker has had plenty of opportunities to kill bats and never has gone through with it....in fact, he's stopped others from killing batman....he wants to beat him, but beating him doesnt mean killing him....it means having batman break his no killing rule...
as for TDK: it doesnt lower the stakes because him wanting to test batman made everyone else a potential victim...hence him fukking with dent, rachel, the prisoners, the mayor, and everybody else in city....