Here's the premise: Take a major DCU story that didn't quite click and alter ONE aspect of it and try to figure out how that would alter it in interesting ways that might make it work. Not a story you hate or fundamentally disagree with the entire premise of, but one that you think had potential, but fell short.
PLEASE NOTE: This is not yet another avenue to bitch and moan about comics we don't like. We've got enough negativity already, this thread isn't here to contribute further to it. So, anyone thinking of posting the predictable reply of not even publishing a story you hate, please don't bother. We all get it, you hate some comics out there. Congratulations. Please vent about it elsewhere.
The obvious choice for me here is the original Crisis on Infinite Earths, but altering the ending so that the small handful of main Earths survived and Roy Thomas wouldn't have to completely retcon away large chunks of his DC output
Another good option would be The Killing Joke, but with Barbara as an actual protagonist in the story, rather than simply a victim for Joker to torture in order to motivate Batman & Gordon. And, no, not like they did in that animated adaptation. Ew.