When the DC Comics section of the Warner Bros presentation at Comic-Con International kicked it a montage of logos flew by the screen. Some of them were expected but some took the audience by surprise. One of the those logos was for Justice League Dark. The reason why it was a surprise was that the most recent director on the production, Doug Liman, had walked away from the project several months before. There were rumors that DC and Warner Bros were looking for a new director but nothing ever came of it. That logo is the closest we've had to a confirmation that this movie is still happening.
Cinema Blend recently sat down with Liman to ask him why he left the production and his reasons sound like a bunch of other reasons people have left comic book movies.
You know, I develop more movies than I make. There's a weed-out process, and it's just that when you get to the comic book one, suddenly everybody hears about them. So, the script never got to a place that was special enough for me. Not for lack of trying.
It sounds like the movie just never came together in a way that Liman could justify continuing to work on it. There were other projects he wanted to pursue and Warner Bros doesn't seem like they're in a hurry to get this movie made. There were other areas of the DCEU they wanted to explore first but judging by that montage of logos Justice League Dark is still in the works.