As James Gunn could tell Scott Derrickson, Warner Bros. has a history of swooping up former Marvel Studios talent to direct future DC movies. Gunn is back the Marvel mix for Guardians of the Galaxy Vol. 3 after The Suicide Squad, but it sounds like Doctor Strange director Scott Derrickson doesn't have any current plans to continue directing in the MCU after leaving Doctor Strange in the Multiverse of Madness.
Several fans have mentioned wanting Scott Derrickson to take his horror background and use it for a Justice League Dark movie. Just today, another fan asked Scott Derrickson if he'd want to make a Justice League Dark movie. He responded by singling out one founding member of that DC Comics league he would be interested in following:
John Constantine! Based on all of the "fuck yeah" responses in the comments, it sounds like fans would be just fine watching a Hellblazer movie from Scott Derrickson. Before Doctor Strange, Derrickson was best known for his work in the horror genre, including Hellraiser: Inferno, The Exorcism of Emily Rose, Sinister, and Deliver Us from Evil.
Scott Derrickson also directed Keanu Reeves in The Day the Earth Stood Still, and Keanu already played Constantine in the woefully underappreciated 2005 movie directed by Francis Lawrence. Keanu has talked about wanting to play the character again. I know nothing in this world is this simple, but I wouldn't say no to Keanu Reeves returning for a Constantine sequel directed by Scott Derrickson. Would anyone care to prove me wrong and make it that simple?
If Keanu Reeves isn't your Constantine of choice, there's always Matt Ryan's John Constantine in The CW's Arrow-verse. Matt Ryan also voiced Constantine in the animated Justice League Dark movie. Or another Constantine movie could start fresh with someone new -- whether famous/established or in a star-making role.
Obviously this is just dreaming at the moment, but if the word gets to the right folks at Warner Bros./DC, maybe they'll jump on the idea. After all, a lot of fans were upset when the news came out that Scott Derrickson wouldn't be making Doctor Strange in the Multitude of Madness, especially when one rumored reason was because he wanted something with a stronger focus on horror.
Scott Derrickson is still connected to Doctor Strange 2 as an executive producer, but he confirmed the mutual parting with Marvel was from "creative differences," so it's not like he'll be a major presence behind-the-scenes. He did tweet that he's working on an R-rated horror film he already wrote with Doctor Strange co-writer C. Robert Cargill. But otherwise, he seems pretty free for Constantine so ... should DC make it happen?