Non-quotable Joker
Was Leto a good Joker? Quote a line.
Nicholson and Ledger had tons of quotable dialogue. People quoted their stuff, and their style, long after the movies left the theatres. I haven't watched Nicholson's Joker in a few years but I can easily quote several lines of his dialogue. Over a year since I've seen Ledger's Joker and I can quote him as well. Just throw out a "Why so serious?" and everyone in the room will recognize it.
I just watched the extended version of Suicide Squad and I can't recall a single thing Leto's Joker said.
Chalk it up to poor writing, but Leto's portrayal was two dimensional at best.