What Nolan did is see beyond costumes or gargoyles and cut to the heart of the Batman character. In general, Batman works best as a figure fighting crime and corruption in a bleak city. I.E. as a crime drama. Most of the recognized great works of Batman feature a form of urban decay or even nihilism (TDKR and everyone Miller ever influenced), cops and mobsters (Year One, The Long Halloween) or pure social anarchy (most Joker stories, No Man's Land, etc.).
While I get that you do not care for Nolan's aesthetic, he recognized that a superhero movie can be more than hero + love interest + jokes + wacky villain with undercooked scheme = $$$.
And while I do not think he is the first superhero filmmaker to do that (Singer should get credit to an extent for his X-Men films), nobody had done it as well as The Dark Knight had or has since. And with $1 billion worldwide and a Best Supporting Actor Oscar, people stopped and took notice.
We have seen the initial reaction of just copying his aesthetic with anemic to mixed results (cough-The Amazing Spider-Man, Skyfall, Star Trek into Darkness and Man of Steel-cough).
But his actual approach--boiling the character down to its essence beyond the mask and crafting a story around THAT--appears to finally be taking root. Iron Man 3 was more of an action/comedy along the lines of Lethal Weapon or Die Hard from the '80s. They even got Shane Black to do it. Thor: The Dark World looks like pure fantasy, right down to its Star Wars-esque cover poster. X-Men: First Class was a stylish period piece that felt as much like a later Sean Connery/early Roger Moore Bond movie as a superhero film. The Wolverine could basically be any Clint Eastwood movie from the '70s, except replace the guns with claws. And Captain America 2 is obviously going for a spy/thriller vibe. Hence the casting of Robert Redford.
This is the true longer impact of Nolan. Forget about making a "superhero movie." Make it more true to whatever genre the character is from. Nolan made the "crime drama" with TDK. And now everyone is slowly starting to follow suit with the cards they have.
You can count on it.