Well, I was unaware of the Joker trivia. But still, not using ANY iconic Batman Villains with the exception of Ra's Al Ghul felt like a bit of a waste.

But Killer Moth has been atleast 2 of DC properties with more than one dialogue. He was in "The Batman" series back in 2000 as a human-moth mutant, Teen Titans as the father of that crazy Robin fangirl.