Why so serious? You're only trying to differentiate your interpretation of an iconic villain from another actor's legendary performance.
Joaquin Phoenix knew as much when he accepted the role of Joker, this time in a film focusing solely on how Batman's arch nemesis came to be—and if anyone was going to approach the challenge with utmost seriousness, it was going to be the three-time Oscar nominee who regularly tackles big questions about the plight of the human spirit in his films.
Reviews of Joker have been mixed, but assessments of Phoenix's performance are not. Regarding what he was trying to do with the character—which may still be subjective depending on your reaction to the movie as a whole—he nailed every damaged nuance. And in a role that heretofore has been a supporting one, albeit as the purveyor of the conflict that makes Batman run, Phoenix has managed to create something new.