At this point Harley is simply Barbie. Same old thing with another obnoxious outfit. Poor Wonder Woman doesn't even get a new outfit most the time - just a variation on the color vibrance. And really, how many versions of Batman does a person need?
How about some new characters? Shazam would look great in a display. Or maybe Mera or Blank Manta. Or maybe a Cheetah so that you have something to go with all those WWs. Or how about Arkham Catwoman. Or Batman Returns Catwoman. We are sorely due for a good Catwoman since the TDK Selina Kyle was hardly a Catwoman and who knows if the Zoe version will be a worthwhile character.
With the exception of more Aquaman (how they haven't made Black Manta yet is beyond me), none of that is particularly surprising. Yeah, the over reliance on Batman sucks, but that's what happens when your movie franchise is the only consistently successful DC thing WB puts out. Again, 99 percent of these issues can be traced back to the DCEU's second banana status, unfortunately.
Like, sorry if someone thought HT wouldn't make something for The Batman, but that's a lot surer financial bet than just about anything else DCEU related.