I can't but help feel that Harley is the poster child for the DCEU. Birds of Prey, SS 2, Gotham City Sirens, Solo Harley, Harley and Joker.......that's a lot of Harley.
And the crazy thing for me is she last appeared in 2016 onscreen. There's a good possibility that it will be 4 years from that date she will reappear and then just a glut of Harley for who knows how long. If a character made such an impact why wait so long and then attempt to have her star in so many movies? That's really overkill IMO.
Gadot's WW is way more popular yet the DCEU isn't trying to get her to star in so many films.