I wouldn't want a pity-Oscar either. Heath deserves better. They blew it to give him the Oscar he deserved, and now it's too late. 
Agree with that, Chrissi. Heath was robbed of his one rightful Oscar and nothing can change that.
But if he
were to get nominated for the Joker, and if he were to win, I don't think it'd count as a pity-Oscar at all. It's just been 2 weeks now... but by the time the next round of Oscar nominations roll around it will have been a year. A long time in Hollywood terms, - to the average Academy member I don't think there will be much strong emotion left, not enough "pity" to make them vote for Oscars for that reason. So much will have happened in the meantime to refocus their attention and stir their emotions. This is not even criticism of them, it's just a realization that such is the impact of time and distance on human nature and especially in an environment and industry so competitively focused on the "hot-thing-of-the-moment" as Hollywoodland.
In fact, if they were to give out an Oscar or nomination for the Joker, it would have to be on the strength of an amazingly, incredibly outstanding performance, one that couldn't be overlooked even if they tried - because they would have to be so awed they'd go against their natural inclination, which very obviously is to reward and to scratch the back of someone reasonable deserving who will be able to later on somehow scratch theirs in return.

Or to reward someone they owe, and who is around to actually acknowledge the downpayment of the debt.

All that said, I am entirely content to wait till I see Heath's actual TDK performance before I speculate more about awards and such. Yes, I've read the interwievs that hyped the performance while Heath was still alive, and yes, I've seen the trailer and that looks good, - but judging the role based on that hype and the trailer and one clip from the film, all of it so obviously parts of a PR strategy designed to stir the fanbase audiences, - that's entirely premature IMO.
The fact that TDK is some way off yet means we have something great and new from Heath still to look forward to. I'm not eager for that to change.