I’m pretty partial to DCAU and the things they have done in the past. This, to me, seems like a bit of a gamble, doing TDKR as a two part movie. TDKR holds a special place in the Batman mythos and could very easily turn out bad. I am glad to see that Bruce Timm is attached as a producer. I also like the choice of Peter Weller as a middle aged Bruce Wayne.
The Dark Knight Returns part 1.
I’d have liked Old Man Eastwood as the voice of Batman. This looks cool. 
Just a note, this is a DCU Animated Original Movie, not an installment in the DCAU. Different things.
One AOM was meant to be in the DCAU - Crisis on Two Worlds was intended to be a bridge between JL and JLU, and if you squint just a little, it still fits in there (there’s still a couple issues - the GL being Hal, not John being the biggest) - but aside from that one they’re unrelated.
That trailer was definitely far more impressive than any of the Nolan Batman movies. It looks like they’ve stayed pretty faithful to the original, but this is only the first installment - how they’ll handle stuff like the Reagan and Letterman expies, the Cold War metaphor, and government-shill-Superman vs. Batman-in-a-cyber-suit and one-armed-anarchist-Green Arrow could make or break the concept.
Either way, I’ll definitely give it a watch.
So it is. I missed that before.
That is a little disappointing. I thought the story was a little close to the episodes Legend and A Better World.