The DCEU's problem has never been the cast, Gunn and co will struggle to find a better Superman than Cavill, a better Wonder Woman than Gadot, a better Harley than Robbie and so on
People originally hated on Cavill and Gadot when they were first cast though... it wasn't until we eventually saw them in action that they changed their minds lol. Same with DC as Bond and HT as Joker etc etc etc. As much as I'll miss those actors, I'm up for the characters being recast and giving other people a chance to make the role their own.
Samara Weaving and Vanessa Kirby would be great. I think they both could play either role.Harley:
Anya Taylor joy
Ana de armas