No room for origin stories
Do you imagine how an origin story movie for Harley Quinn could play? I don't. And, thankfully, I won't see one. And that is because Harley's origin has already been told in Suicide Squad. Which is great. The character, with her chaotic and psychotic nature, will be thrown right into the action as soon as the movie starts.
If there is one great thing about the DCEU, it’s that we don't actually have too many movies focused on origin stories. The heroes and villains are already fully formed. So there is no precious time lost on uninteresting details from the previous life of the character.
And with someone like Harley Quinn, especially if she’s in a relationship with the Joker, the movie has to be a roller-coaster from the beginning until the end. I wouldn't mind some flashbacks, just to let me breathe, though.
