He did an awesome job
voicing the joker, but he's way too fucking old and not a good enough actor to pull it off in live action. Crispin Glover
could be a really good joker, but first he'd need to work on his voice a bit. He's an awesome actor but that kinda nasally mcfly voice wouldn't fit with the joker
But yeah, it's a very important role and I'll be pissed off if they fuck it up right off the bat by casting the wrong guy.