Sending Joker back Harley Quinn’s way, however, would give the character a clear path following Justice League, assuming Zack Snyder’s goal in incorporating him is to give the character a chance to work his way back into the DCEU.
I can’t say I’d like to see this Joker and Harley mend their relationship, but I would love to see them go to war against each other as ex-lovers.
My guess is that it’s far too late for James Gunn to incorporate the character into what he’s doing, not that he should feel obligated to in either case.