It turns out that the reason Gavin O'Connor appears to be no longer writing and directing Suicide Squad 2 is because the story was far too similar to another DC project in development. Shortly after kickstarting their DC Comics-based shared movie universe in 2016 with Zack Snyder's Batman V Superman: Dawn of Justice, Warner Bros. quickly moved to expand the then-burgeoning franchise with David Ayer's Suicide Squad, thus featuring the first live-action feature adaptation of DC's Task Force X.
Suicide Squad notably starred Margot Robbie as Harley Quinn in her first live-action appearance along with Will Smith as Deadshot and Jared Leto as the Joker, among plenty of others. While it certainly wasn't a critical success, it was an irrefutable commercial achievement for the studio, which is why they quickly started developing a sequel as well as a few potential spinoffs. One of those spinoffs, Birds of Prey, was recently given the green light and will now release in February 2020. But, it appears that moving that movie into pre-production has inadvertently forced the current team behind Suicide Squad 2 to vacate the project.
According to Variety's Justin Kroll, Gavin O'Connor exited Suicide Squad 2 because the story that he recently co-wrote with Todd Stashwick and David Bar Katz - which Stashwick recently said the sequel's script was turned into WB - was apparently too similar to Cathy Yan's Birds of Prey, which is based on a script by Christina Hodson. Since WB greenlit that movie instead of his, O'Connor reportedly got frustrated and left. And so, the studio has now hired James Gunn to write Suicide Squad 2 and potentially direct.
This news obviously comes on the heels of Gunn being fired by Disney as the director for Guardians of the Galaxy Vol. 3 due to a plethora of old tweets of his, which contained jokes about rape and pedophilia, resurfacing online. Since the filmmaker was originally slated to start filming Guardians 3 in early 2019 in order to make the movie's potential 2020 release date, his schedule was blown wide open, save for the secret Sony horror movie he produced, which is now expected to release in 2019.
Aside from the big news that Gunn has gone from Marvel Studios to DC Films - though it's not surprising that Warner Bros. would hire him considering that the studio gave him his first major writing gig with the early 2000s live-action Scooby-Doo movies - what's interesting is the direction he might take the characters and the story. While little is known about what O'Connor's Suicide Squad 2 would've entailed, judging by what has been reported about the Birds of Prey movie, it seems it could've seen Task Force X restoring order in Gotham City that had been left unprotected by Batman. But that's something fans will just have to wait and see.
Source: Justin Kroll