Well, it appears Warner Bros. is already throwing in the towel and rebooting the DCEU. A pity really after their first real smash hit in Wonder Woman that they would be doing this, but apparently at Justice League panel at SDCC today the announcement was made. That they are indeed retooling the Flash movie into adapting instead the event Flashpoint.
The story featured the Flash thinking the Reverse Flash changed the world into an even grimmer place (Aquaman and Wonder Woman are tyrannical warlords fighting each other, Batman is not Bruce, but his father). it all leads to the Flash changing reality again which lead into the New 52 (with a timely assist from Pandora, who then revealed to nothing but a pawn for Dr. Manhatten cause COMICS!).
This is so not going to be a 100% faithful adaptation, will it? With all that going on? With all that grittiness and darkness? We'd say when this movie would be out, but considering the level of creative hell, the Flash movie has been in the past few years. Well, we'll just keep you updated whenever we can on this.