It looks really good, although my biggest concerns are A). The R rating. Only a few superhero movies have ev ever done well with such a hard rating, and I'm having a hard time seeing this one pull away like Logan and Deadpool, as Deadpool was a comedy, and evryone all ready knew who Logan was. Evryone knows the Joker, but not this Joker, and might get turned off for it.
B). The heck was up with the lady in the bath? That entire cut of the trailer made me uncomfortable and just didn't make sense with the rest of the trailer.
Overall, I like the idea of going into what makes Joker mad, I feel like it could be a really interesting movie, and with what looks to be an 80s setting, a really cool atmosphere.