Azrael is definitely the sticky wicket. Without AzBats, doing Knightfall seems far less interesting.
I imagine Azrael (the mini series) being a prelude to the first film which would have to end with Batman being broken.
That would mean that the rise and fall of AzBats and Bruce's eventual return would be left to a second film.
Kinda makes the second film a little bunchy. Seems like it could work quite well if done right.
A Netflix series would do the trick without any question.