Re: If they reboot Batman and cast a new Joker...
Let's face it, if it takes them 6 years to make a new Batman, it'll be virtually impossible to predict casting. They'd probably end up going for a relatively obscure up and coming actor like Dane DeHaan who will probably be a much bigger deal in the next few years.
I think they finally have an opportunity to actually have someone play the Joker this time around. As great as the first two were, Jack Nicholson was basically being himself and Heath Ledger was playing a psychopathic Monster more than anything. Mark Hamill had it down pat, but he never played him physically on screen.