I don't watch Gotham anymore (TERRIBLE show), but this is AWESOME news. I never did like "Jerome" because giving the Joker an origin just ruins his mystique. I have nothing against the actor who plays him, he does a good job with the role but his character was never the Joker for me.
I'm glad Fox recognized the Joker needs to be a little mysterious. I just hope they get someone who will be great for the role, but preferably someone who isn't too old like a lot of the actors are on this show for the characters they are supposed to be playing.
I think that you are in the minority, as MOST of the fans of Gotham really have accepted Jerome as being the Joker, and anyone replacing Him would be seen as being a fraud!
They might have started out not having Jerome as Joker, but the time to replace was when they killed him off, and that was to be the time real Joker rose up, but resurrecting Jerome made that a done deal, so have Jerome fall intoit Chemicals when Bruce dons the Batsuit, or else have Jim Gordan become the Joker at end of series!