I know a lot of comic enthusiasts hated the first film because it gave us an entirely different Joker than the character from the Batman comics.
To me, it was an okay, but flawed, film. It developed slowly by design, but it was painfully slow in spots and in many places just too awkward in setting up his character. There were even a couple of moments I felt were a little dumb. I liked it overall, but it was far from a great film. It could have used some serious editing imho. It was almost like nothing happened until the last 10-15 minutes.
I've been hoping this film "takes off" from the end of the first. I certainly hope it doesn't do the same overly slow, overly awkward burn the first film did. If that's how it's structured, I'll probably skip it.