I've seen the film three times now. I bought the DVD and it'll probably be watched several times. Each time I see things in the character that are intriguing. To me, it's more a case study of mental health, trauma, and a man living in a world that doesn't much care. The 'Joker' persona is almost understandable, especially as Arthur's mental health deteriorates and his delusional states become worse.
All in all I was surprised by it and was grateful it didn't become just another 'origin' film. It didn't look that way from the previews, and it really stayed away from a 'cartoon-ish' vibe. Joaquin Phoenix gave a master performance