In many ways, that last element was the beginning of the end for Dick Grayson, boy wonder. Although his stayed in the Robin role through 1984 — he quit in New Teen Titans No. 39 — he had become increasingly estranged from Batman throughout the 1960s and '70s. On a narrative level, it made sense — he was growing older, had his own friends (Teen Titans, with Robin in the leadership role alongside fellow sidekicks Kid Flash, Wonder Girl, Speedy and Aqualad, launched in 1964's The Brave and The Bold No. 54) and had already ditched the "Boy Wonder" tagline in favor of the more awkward "Teen Wonder."
All of these experiences didn't just prepare him to go it alone as "Nightwing" (He took on that identity in 1984's Tales of the Teen Titans No. 44), they also ensured that he would be a more carefree, fun-loving crimefighter than his former mentor. His early childhood in the circus might have left him with both acrobatic skills and an understanding of the value of teamwork, but it was growing up surrounded by other superheroes — and surviving attacks by all kinds of supervillains — that ensured that Dick Grayson would be someone that understood his life was at once both ridiculous and, on occasion, extremely dangerous, making him all the more appreciative of those around him.
Today, Dick Grayson belongs at the center of a social circle that includes the "Bat-family" — Batman and various associates — as well as Superman, the no-longer-teen Titans and the spy organization known as Spyral. He has a "best frenemy" in the form of Midnighter, star of DC's Midnighter and Apollo series, and he remains someone others look to to put things in perspective. He is, in many ways, a superhero who sees his job as fun… which might put him at odds with the rest of DC's cinematic universe, as it currently stands.
In pure story terms, there is space for Nightwing to exist — while Batman v Superman: Dawn of Justice and Suicide Squad teased a dead Robin, it wasn't definitively stated that this was Dick Grayson, and Ben Affleck playing an older Batman allows for a former Robin to have grown into an adult himself. Tonally, however, it'll be interesting to see if Nightwing breaks from what's gone before cinematically and stays true to its comic book roots, or vice versa.