I think with how most film versions of Joker tend to be influenced by musicians in some way (Prince with Nicholson, Sex Pistols/Iggy Pop/ Pete Doherty and a rumored-but-not-confirmed possibility of Tom Waits for Ledger, I guess maybe... "If David Bowie did trap" as I've heard it once described for Leto), I wouldn't mind it at all if the next Joker had some influence from Mike Patton.
Dude pretty much IS The Joker of the music world. His projects like Mr. Bungle suit the character very well . I wouldn't even mind if he voice acted for the role in something and/or composed his theme etc