The Dark Knight is a better film than The Dark Knight Rises for several reasons. For one, its story is more tightly written - everything we see on screen happens for a reason, and the different subplots all intertwine flawlessly. Whereas the final film in Nolan's Batman trilogy simply tries to do too much, forcing in too many characters and subplots that could have been condensed, combined, or left out entirely, and giving the story a rushed, chaotic feel. There is also a constant sense of self-consciousness about the film - the viewer gets the feeling that Nolan and his team carry with them the weight of the acclaim The Dark Knight earned, and are constantly trying to top themselves, rather than tell a new and distinct story which will stand on its own merits.
A perfect example of both of these aspects is the opening scene in which Bane and his thugs hijack a plane in order to kidnap a nuclear physicist. Their plan comes off as unnecessarily (and somewhat absurdly) complex - why did Bane and his men have to be captured, and why did the whole thing have to occur while the plane was in the air? This sequence calls to memory the bank heist scene in The Dark Knight - both are opening action set pieces which introduce the audience to a new villain. However, the bank heist serves its purpose far more successfully. It contains great action while not being overly complex, it moves the plot forward by establishing that The Joker is stealing the mob's money, and most importantly, it tells us a great deal about the villain. While Bane's scene is an introduction to the villain in only the most literal sense that the audience sees him and experiences his actions for the first time, the bank heist demonstrates through this one scene that The Joker is a ruthless, clever loner operating on his own terms and unafraid of pissing off the wrong people. By the end of Bane's plane heist, all we really know is that he is a big scary guy with a weird mask.
However, returning to the question of whether The Dark Knight Rises is better than The Dark Knight, the more complete answer is that these two films are both parts of a greater whole, and though drawing comparisons between the two is inevitable, trying to determine which one is truly "better" is akin to trying to decide which chapter of a book is your favorite. At its core, Nolan's trilogy is really the story of one character - not Batman, but Bruce Wayne. Looking at the trilogy in terms of dramatic structure, Batman Begins serves as the introduction, establishing a back story and setting up the character of Bruce Wayne for further development. The Dark Knight provides the rising action of the story, expanding the characters and raising the stakes while building toward the climax. And The Dark Knight Rises brings the climax and resolution of Bruce Wayne's story. And it is here, as a conclusion of Bruce Wayne's story arc, where The Dark Knight Rises truly excels. The ending of this film also serves as the ending to the trilogy, and The Dark Knight Rises delivers an exceptional finale.
So ultimately, when discussing these films, here's what I am going to say: I consider them all to be excellent movies, both independently and as parts of a whole. Do I have a favorite? Yes. I think The Dark Knight stands above the rest in terms of filmmaking, in terms of story, and in terms of personal preference. But does that mean that I wouldn't call all of these movies great? Of course not. I love the trilogy Christopher Nolan has given us, and I am sure that it will join others such as Star Wars and The Lord of the Rings in being considered one of the greatest film trilogies of all time.
