Joker was pretty awesome movie but this is not the Joker. The Joker is suppose to be a criminal mastermind and this Joker knows nothing about being that mastermind. Joker also is a lethal fighter this Joker is beat up several times. Joker has complete understanding of the Gotham underworld and is considered the most feared criminal. This Joker is more of a mental patient going thru a lot of problems. I don't see how this joker becomes the joker that fights batman, he's just not equipped for it. Lets not even mention the age difference by the time Batman would be Batman this Joker would be in his late 50's. I'm not sure they're telling the true originals of the Joker we know, but a different version where Batman doesn't exist. This Joker could also be a dream, not the original story at all which has been flirted by the director.
When you look at Dark Knight Joker... he masterminded essentially catching and killing batman, outsmarted the entire mob, bank robberies, blowing up buildings, taking down a helicopter, defeated nearly the entire police force, and more.
This movie could have very easily been a movie about a mental breakdown. Either way this Joker could never become the real joker because he just doesn't have the skills. Great movie, different version of Joker, but nothing can top Heath Ledger. I do however feel this Joker should win best actor because his performance was amazing no doubt. I just don't see how this Joker based on what he knows, can do, his experience as a criminal can become a mastermind who could take on Batman.
If they make another one, hopefully we find out, if this was just Joker daydreaming, and the real live joker is ruthless mastermind. Have to wait and see I guess.