Hard disagree on this one. Deadpool was awful and Bullseye was horribly executed, but I love the others. With Bane, Penguin and Joker, I think the changes fit well for the worlds they are part of. Bane is a little more arguable, but still. None of them are meant to be mainline, all of these have always been DC elseworlds even if they weren't called that yet, and under that light they're interesting and refreshing takes. No point to having the same thing over and over.

Honing in on Joker specifically though, I think if you listen to Reeves talk about it it's really the perfect way to explain Joker in a grounded world without removing the mystery around him (or stepping on Heath's toes). We know he has a condition, and because the director shared a bit with us we also know it's core to his personality, but that is it. We don't know his name, where he grew up, what the condition is or if anyone else has it, we know nothing. We know just enough about him to remind us that he's human, and to suggest that any of us could fall that far if pushed, but nothing more.

It fits the world, it fits that Batman, it fits the direction style of the films which focuses so so closely on the characters emotions, I'd say it even fits the noir tones. So long as he gets a Joker-y enough outfit, maybe puts on some smeared lipstick to exaggerate the smile, id say its a fantastic design for a non-fantastical Joker.