Flash to reset DCU for James Gunn
It appears that they may use this film to reset the entire DC universe for James Gunn, similar to how it was done in the novel the second time Barry tried to undo his first.
In the comics, Flashpoint was used as editorial leeway to reset the DC Universe in a line-wide reboot called the New 52. See, when Barry eventually realized he needed to undo the time travel he’d done, he donked it up again, resulting in a permanent change to the main DC setting, resetting some continuities entirely and folding in some of the company’s non-canonical siloes, like Wildstorm and Vertigo, into the main line.share
Lots of fans have speculated that The Flash movie could do the same for Warner Bros.’ DC films line. And they may be right. In his recent video announcing the new direction of DC films, WB executive James Gunn said that The Flash is “a movie [...] that resets the entire DC Universe.”
https://www.polygon.com/23597010/batman-michael-keaton-flash-movie-christian-bale