We already had Jim Carey...
Seriously, I think the Riddler would be an excellent choice for the next Nolanverse Batman film. IF they don't go the Joker clone route (which, I felt Schumacher did with his version of the Riddler).
Just someone who commits normal crimes and is pretty good at it, too, except he feels he has to leave behind a clue, in riddle form.
Right. You want someone who's definitely as manic as The Joker, but who goes about it in a much more sedate sort of way.
I still think David Hyde Pierce would be brilliant. I don't give a damn how old he is.
Also, while we're demanding things I demand a bottle of Jack Daniels and Mika Tan's undivided attention for a weekend.