Re: The Reboot Joker
Neither Arkham City or The Dark Knight Returns allude to it in that way. They both have Batman say he should have killed the Joker because every time he lets him live he just kills some more people.
If anything TDK showed what you're saying more than any comic book has, because Batman blames himself for the Joker killings, and even says he inspired madness and death when he should have been inspiring good.
"Sometimes I remember it one way. Sometimes another. If I'm going to have a past, I prefer it to be multiple choice!"
- The Joker