And Harley could work really well, if they lessened her sweetness.
I want the characterizations of characters to be more comic like than what we got in the Nolan's. Not that I didn't mind the changes for Nolan's vision, but that's over now.
Harley should be handled in a certain way however, that changes things to a degree.
I like it how she's a genius, and strict. Normal.
Then Joker breaks her slowly down. She loses her sanity and gains a twisted love for him.
It sounds mushy when you see it in mediums.
But they can handle it more adult, and Harley for that matter, too. We don't have to Nolanize her to get her on screen - stripping her of her key elements.
But we also can't have her as annoying as she is in other things. ..but of course, that's Harley's charm...
So, it would be a challenge to convey her in the right way.