I don't know, I like what they're doing with Leto's iteration. It feels kinda like a take on Hamill's Joker in the Arkham series, but with tatts and a grill. Those aesthetics are things that I can get used to, though. It's definitely going to feel different than the other on-screen portrayals of the character overall, and I like that.
It's better to try to go down a more original route instead of trying to rip off somebody else's take and not give it justice. They could've gone with Bale as Batman and find someone who could replicate Ledger's Joker and call it a day, but they didn't. And it's going to do them more good than harm in the long run for doing so.
My thoughts on Leto's Joker aside, I agree that Margot will probably be the most talked about person coming out of the film. Well, her as well as Leto. That's their movie basically. Will Smith who?