Thanks to Zack Snyder's recent comments that Man of Steel was almost connected to Christopher Nolan's The Dark Knight trilogy, the assumption could be made that Christian Bale would have made a return as Batman had the DCEU followed a similar trajectory. While Man of Steel ended up being it's own entity that kicked off the connected universe of DC films with Ben Affleck as Batman, it's possible that Christian Bale's Dark Knight could have made a return albeit in more of a support role, seeing as how The Dark Knight Rises ended with Joseph Gordon-Levitt's John 'Robin' Blake taking on the Bat-mantle.
Recently, Zack Snyder has confirmed that there were early considerations during production about connecting his 2013 Man of Steel film to Nolan's Dark Knight trilogy, though those ideas never came to fruition. This was most likely due to The Dark Knight trilogy's tone being much more grounded than more fantastical elements that have since been featured in the DCEU such as aliens and superpowers. However, it's hard not to wonder what could have been, especially considering certain DC films currently in production that will feature Batman such as 2022's The Flash, starring Ezra Miller in the titular role.
While Gordon-Levitt's Dark Knight would have most likely been the primary Batman going forward in this theoretical version of the DCEU, the continuation of his narrative could have also seen Bale's return in a retired mentor capacity, not unlike the version of Bruce Wayne seen in the animated Batman Beyond series. However, it's also possible that Bale's Batman could have taken the place of either Micheal Keaton or Ben Affleck, who will both play their respective versions of the Caped Crusader in The Flash, reportedly serving as mentors to Barry Allen as he runs through the multiverse.
That being said, it's possible that The Dark Knight trilogy's more grounded tone and nature would have tempered more of the DCEU's wilder elements across the board. While Barry Allen (and other heroes in the Justice League) could have still been introduced, perhaps elements such as The Flash's ability to time-travel and jump to other realities would have been diminished, or perhaps not have been depicted at all. Even so, Christian Bale could have still been featured as Bruce Wayne had he been the primary version in the DCEU as opposed to Ben Affleck, and Gordon-Levitt's journey as the new Dark Knight could have been featured as well.
While potentially seeing more of Christian Bale's Batman would have certainly been interesting, it's probably for the best that Snyder's Man of Steel and the following DCEU didn't connect with The Dark Knight. However, nothing says that Bale or Gordon-Levitt's Batman couldn't be briefly seen in cameo roles in The Flash as Barry travels the multiverse in his upcoming film. After all, Barry will reportedly be spending some time with Michael's Keaton's Bruce Wayne in director Tim Burton's world of Batman films, so why not a quick trip to the Nolan-verse as well?
