Although there are no plans for Zack Snyder to return to the DCEU movie franchise, he’d hoped to introduce Batgirl and a new Robin to the continuity, which would have had fascinating effects on Ben Affleck’s canceled The Batman in early 2017 in order to let another writer tackle the script, and after some shuffling Warner Bros. placed director Matt Reeves at the helm of a much different film, set outside the continuity of the DCEU.
Zack Snyder, similarly, had big plans following the events of Superman's eventual sacrifice to defeat Doomsday finally pushes the Dark Knight back into his more noble methods, but this arc would have continued in his solo film and would have been affected by Batgirl and a brand new Robin.
Zack Snyder, notably, voiced plans to introduce Batgirl and the Carrie Kelley iteration of Robin to the DCEU. When answering fan questions on social media, Snyder revealed that he’d wanted Carrie Kelley to succeed the late Dick Grayson as Batman's iconic sidekick, which would be yet another instance of Frank Miller’s The Dark Knight Returns influencing the DCEU. In a 2021 interview, Snyder also voiced plans to introduce Barbara Gordon, with her father, Commissioner James Gordon (J.K. Simmons), on his way out of the franchise. Considering the planned storyline for Ben Affleck’s original version of The Batman, these two new proteges would have fit quite well into Batman’s long-term characterization.
With Batman returning to his more heroic self after the events of Justice League, perhaps training Carrie Kelley as the next Robin would help Bruce cope with the loss of his adopted son, while also training the next generation of superheroes. Snyder never specified exactly how Jim Gordon was set to leave the DCEU, but Affleck's planned solo film may have seen the GD legend meet a grim end. Reportedly, Affleck's vision for The Batman would have seen Deathstroke - who learned of Batman's secret identity in the post-credits scene of Zack Snyder's Justice League - systemically dismantling Bruce Wayne's life by killing those closest to him. Given that Batman doesn't exactly have a long list of close friends, it's a safe assumption both Gordon and Alfred could have been on Deathstroke's list.
The loss of his surrogate father and a long-time friend in Alfred and Jim Gordon, respectively, could have risked Bruce relapsing into the despair and brutality Batman showed in Dawn of Justice. His partnership and responsibility for Carrie Kelley, and potentially the rise of Barbara Gordon as Batgirl, could have conversely been what kept Bruce from repeating his past mistakes. This would also have allowed Deathstroke to appear in the potential apocalyptic Knightmare future that Dawn of Justice and Justice League foreshadowed. Snyder’s plan was for Batman to avert the Knightmare future and sacrifice himself to defeat Darkseid and save the Earth (and countless other worlds) from his conquests. Ben Affleck’s Batman film would have solidified Bruce’s adherence to heroism through mercy and restraint, setting him up for this heroic end. With Carrie Kelley as Robin and Barbara Gordon as Batgirl, Bruce would leave behind a legacy of new heroes to continue what he started as Batman.
