Saying a recast would be pissing on anyone's grave is complete and utter ********.
Stop acting like Heath was a god. He wasn't. He was a ****ing great actor who gave an absolutely amazing performance that should be celebrated.
No more, no less.
You do his memory an injustice with all this fake outrage. Before his death a lot of people criticized what they saw.
Now, there is nothing but praise. I myself have nothing negative to say about his job, he is amazing in the film, but you make it seem less of an achievement when you talk about him like a god. He got a royal flush with the Joker, no doubt. But with this gushing over him, you make it seem like he won with a stacked deck, you put a filter on it that can make people think, "Oh, if he didn't die maybe no one would be saying this." Its great to talk about how great he is in the movie, but don't bring these other elements into it.
If he didn't die, it would be "Even though I didn't like this this and this, dammit, he did a ****ing great job." Now, its clearly "He did such an amazing job, everything was perfect." And when people see that, they will think that maybe his death had something to do with it.
And nonsense he couldn't be topped. People said the EXACT same thing about Nicholson, and I don't think anyone believes that any more. Would it be hard to find an actor who could match or even do a better job than Heath? Yes, very, and it would be done the same way Ledger surprised us all.
I say celebrate his work and enjoy the hell out of the movie just as everyone involved wanted. If there is a third film and the Joker plays a part, we'll see how it ends up, but don't cheaper Heath's performance with all this.