Messy DCU Shakeup Led to Changing The Flash's Ending Completely
While The Flash TV series on The CW is approaching its conclusion with Season 9, after enjoying a period of success, even if its viewership and ratings had steadily declined in later seasons, The Flash movie from Warner Bros seems to be in trouble even before its release.
Besides a number of scandals involving Ezra Miller, who plays the titular superhero, there are rumors that the movie's delay is a result of major reworks, to which the movie has been subjected.
Allegedly, the movie originally ended with Barry Allen returning to his original timeline, and, to his surprise, finding that Michael Keaton's Batman and Sasha Calle's Supergirl now had always been a part of his world.
That was needed to enable the former to appear in several movies, which either definitely were in development, primarily the now-canceled Batgirl movie, or were rumored to be scheduled for relatively near future, such as a Batman Beyond live-action movie, and a Crisis on Infinite Earths movie.
However, with DCEU being transformed into DCU, there is an ongoing shakeup of plans. As mentioned above, the Batgirl direct-to-streaming movie has been canceled outright, a rather unprecedented turn of events, almost certainly indicating that the movie was epically and irretrievably bad. And Keaton's return to the role of Batman now increasingly looks like a one-and-done deal.
So, as rumors go, the original ending to The Flash got scrapped, alongside with the Batgirl movie and earlier plans for the future. Keaton and Calle's characters will not appear in the "base timeline" of DC cinematic universe. Allegedly, a cameo by Henry Cavill 's Superman also had been removed.
The decision was supposedly made by James Gunn and Peter Safran, once they were appointed to lead DC Films (now DC Studios). Rumors do not make clear what role The Flash (the character and the movie) will play in what amounts to currently ongoing reboot of DCU. In the comics The Flash's ability to travel through time and dimensions had been used to remake the timeline for the sake of a continuity reboot before. It remains to be seen whether it would be employed in the same way by Gunn and Safran.
The Flash is currently set to premiere on June 16, 2023.