There is a simple, unavoidable problem that rears its head any time a sequel for an ensemble movie begins development: because all of the stars have different schedules, not everyone can necessarily be available to film at any time that may be considered otherwise optimal. This is evidently an issue that is currently being faced behind the scenes of Warner Bros., as they would like to get to work on Suicide Squad 2, but find themselves held up by Will Smith's other commitments:
With Margot Robbie's Harley Quinn set to get exposure in developing Gotham City Sirens and Joker & Harley projects, Will Smith seems like he is positioned to be the true headlining star of Suicide Squad 2, but new word suggests that WB may have to wait for the star to be available. The above Tweet comes from the personal account of Variety reporter Justin Kroll, who is saying that developing projects Aladdin and Gemini could cause production on the Suicide Squad sequel to be delayed until Fall 2018.
This whole situation is certainly one that the producers behind Suicide Squad must have seen coming when they first signed Will Smith to play Floyd Lawton a.k.a. Deadshot. While they probably locked him in for a multi-picture contract, that doesn't mean that they own his schedule, and he remains one of the most popular A-listers around. The folks at DC Comics are probably wiping their brows with the news that Bad Boys For Life probably isn't moving forward, as that blockbuster probably would have pushed Suicide Squad 2 plans back even further.
Right now, the whole production schedule for the future of the DC Extended Universe seems to be totally up in the air. At San Diego Comic-Con back in July, Warner Bros. announced a full slate of upcoming projects, but failed to mention when any of them will actually be coming out. Aquaman is slated for release in December 2018, and Shazam! just started production this morning, but beyond that we don't really have a full idea of what's going on. We definitely know what we are getting a Suicide Squad 2 (it was highlighted as part of the official title announcement), but it seems like we may not see it until after a good number of the other projects currently in the works.
We've created a special Upcoming DC Movies Guide specifically designed to keep track of every weird and unexpected moves made within this franchise, and Suicide Squad 2 is very much a project that we are keeping on our radar. If this new rumor is true and production won't actually start until Fall 2018, that means its possible that we won't actually get to see the sequel until some time in 2020 (unless it winds up being a small-scale affair that can come out in winter 2019). We don't know enough to precisely say right now, so we'll just have to wait for more updates.