Can't it stop being about ledger for ten seconds? If he hadn't died just after it really would never matter to anyone that he did do it. I think they aren't recasting purely to avoid the worst kind of retard strong nerd rage it would give them rather than respect for him, I'm willing to bet Heath doesn't give a shit about whether or not there is a new joker. If handled with proper writing and the correct actor another joker could be awesome, he escapes arkham and has his face completely changed and lives a whole new life as somone else with the Red Hood secret identity while Batman is busy chasing the jokers ghost the new him is busy fucking him around.