An amnesiac John Doe would be the only real way to do this and stay true to the Joker mythos.
This presumes that there is only one Red Hood and not a gang of them. If it is a gang, then the leader can always escape and no one in the gang knows who he is.
Also I just thought of something they might want to do on the show, have Bruce remember about the time he was in the woods and fell into a hole that led to the bat-cave under the manor.
T thought that he was goijn to roll down the hill and fall into the "bat cave"
And the Joker of Gotham does not have to be the one in either comics/movies though, so anyone could be him..
Do like the idea that he and Bruce might have had a :relationship: from teen years forward...