As great as Christopher Nolan's Dark Knight trilogy is, it leads to a problem portraying Batman within the DCEU. Batman is one of the comic book world's oldest superheroes, and also one of its most famous, leading to a string of live-action and animated adaptations of the Caped Crusader's adventures over the years. Depending on when one first became a Batman fan, there's a chance their favorite Batman actor might be Adam West, or Michael Keaton, or even Ben Affleck. Still, perhaps the most common choice is Christian Bale, for his work in Nolan's award-winning Batman saga.
Depending on who one asks, Nolan's Dark Knight trilogy is often called the greatest series of superhero movies ever made, with The Dark Knight individually often considered the greatest superhero movie of all time—in no small part due to the late Heath Ledger's iconic performance as the Joker. Given that, it also goes without saying that many deem the Dark Knight trilogy as being cinema's best movies starring Batman, with the performances found within them also often singled out for praise.
While some, such as Dark Knight trilogy in the DCEU would've been for the best, since its existence as such a beloved piece of Batman entertainment creates a kind of no-win situation for the DCEU's portrayals of the character. If Batman goes dark in the DCEU, it invites immediate unfavorable comparisons to Nolan's work. On the flipside, if DCEU Batman goes too light, those who love Nolan's grim, realistic take will be instantly turned off.
With a nickname like The Dark Knight, it might seem right that Batman always be portrayed in a darker way, but at the same time, that definitely hasn't always been the case. The Adam West TV show and the Joel Schumacher Batman movies of the 1990s were certainly full of camp silliness—ittedly to mixed results. What Nolan's trilogy did though was take the dark dourness found in some prior Batman iterations and combine it with a more grounded, almost crime thriller-esque style. Millions upon millions of people fell in love with Nolan and Christian Bale's version of Batman, and it's likely their work will continue to overshadow any new take DC attempts for at least the next several decades.
While not technically part of the DCEU, director Matt Reeves' Gotham City that Nolan and Bale created, and with that unlikely to happen, the shadow of the Dark Knight trilogy will continue to loom over the DCEU.