While Batman is the one who taught Nightwing everything he knows about crime fighting in DC Comics, Dick Grayson has proven that he is objectively better than his mentor ever was. Dick Grayson first joined Batman after his parents were killed by the hands of a Gotham crime boss. Dick was an acrobat with a traveling circus along with his parents, and when they got to Gotham, “Boss” Tony Zucco tried to intimidate the circus owner into paying him protection money. When the owner refused, Zucco had Dick’s parents killed. After that tragedy, Bruce Wayne took Dick Grayson in as his young ward and eventual sidekick, giving him the superhero name "Robin." As Dick grew older, he decided to become a superhero in his own right, at which point he actually surpassed the Caped Crusader himself.
In Batman #688 by Judd Winick and Mark Bagley, Dick Grayson hits the streets of Gotham, not as Robin or even Nightwing, but as Batman after his predecessor was believed to be dead. Between Batman’s disappearance and Dick taking up the mantle, crime in Gotham reached an all-time high as it was left completely unchecked. However, when Dick finally put on the suit he was seemingly trained to wear, that completely changed.
Not only were criminals being stopped just as they were when Bruce Wayne wore the cowl, but arrests were significantly higher with Dick Grayson as Batman. When Dick would go on his crime-fighting missions, he wouldn’t just beat criminals to a pulp and instill fear in their hearts, but he would make it easier for law enforcement to prosecute the alleged offenders. During a newscast in this issue, the anchor reads a quote from Gotham City Police which stated, “Batman is leaving crime scenes so clean that it stays within the law, and evidence can be gathered untainted. We don’t know where this new approach is coming from or why, but we like it.”
The second sentence in the quote tells readers that Bruce didn’t care about making the criminals he beats up easier for the police to arrest. His mission was to make those who would break the law so afraid of him, that they wouldn’t do it again. Bruce’s Batman held himself up as the end-all be-all of justice in Gotham, whereas Dick’s Batman knew he needed to work for the police to keep the criminals he stops off the streets.
Dick Grayson’s extra care to preserve a crime scene could stem from his time as a detective, though he has always been a smart and observant student under Bruce Wayne and he likely just came up with ways to improve on Batman’s methods to curb crime in Gotham. Regardless for why he does it, Nightwing’s methods in crime-fighting are objectively better than Batman’s as he works with the police to help them obtain evidence that will actually lead to the convictions of the criminals he stops.