Watched it on Saturday, and while it being so dark, angry, and sad I expected to be thinking about this for a while, I didn't expect to think about how this actually worked as a Batman movie.
The ending, with not the Joker, not a gang member, not a drunk, but the philosophy of the Joker having been what killed the Waynes, and the peoples' embrace of Joker was a really interesting way to show the fight between Batman and Joker being about the hearts and minds of Gotham (even without a Batman and even if Joker really doesn't care about them).
Phillip's creation of a not confident, not exactly the brightest person with mental illness, and Phoenix's execution of it is an impressive feat. Their ability to take this sad, angry, broken man and slowly turn him into the chaotically happy and evil person was pretty damn good.
It actually reminded me more of Mr. Robot, which I didn't expect, but seems somewhat obvious now with the Joker masks replacing the Guy ****es masks and the occupy Wall Street vibe.