A well-written Joker is awesome (see: Batman the Animated Series and The Dark Knight). A badly written Joker (see: Suicide Squad) is . . . . . sad.
The Dark Knight worked well, but even then all of the depictions of The Joker have been just plain boring throughout the various media. He's used too often and does the same exact thing. He's a closed book. He's establishment, ironically enough. His rules need to be broken and his character brought to the center more, especially considering the context of being a US comics character means little to no development or change.