Marvel doesn't have to rely on the director's award winning capabilities, they make movies heavily based on their comics without altering it them too much in adaptation.
While not carbon copies of the comics, they are distinctly their source material.
Batman was not.
Also, Marvel's movies really don't need to be award winning movies in anything other than maybe effect-based categories. To be honest, no comic movie really needs to be. Nolan is too boring for Marvel.
I'm cringing right now. Its a bad time in cinema when people don't care about talented directors with a real vision, because 'these types of movies don't NEED it.' That's the kind of mentality that will keep Marvel from ever making a great film and its a damn shame. They should take the character's seriously and that means getting some talented people to make GOOD films, not GOOD COMIC films. The MCU took no risks in Phase One due to this mentality which is why every solo film is fun entertainment, nothing more, nothing less. They actually gave Whedon some creative control in The Avengers which is why its actually very good. The director should be the most important aspect of the film. Marvel knew that for The Avengers and it paid off. They need to start doing it with their solo films and based on what Shane Black did with Iron Man 3, I think they are learning, even if some of their fans aren't.
You can stay true to the spirit of the characters and stories while still making better films with better, more artistic directors that take risks. With higher risks comes higher rewards, but sometimes the risks backfire like Ang Lee's Hulk. However, I'd much rather have 4 great superhero films and 2 terrible ones, than have 6 entertaining fluff pieces. Nolan's films are not direct adaptions of the comics, but they are, for the most part, true to the spirit of the Batman mythos. Batman: Year One, The Long Halloween, The Killing Joke, Knightfall, and No Man's Land influences are huge. Now, I wouldn't say Nolan is an auteur, but he's the closest thing to an auteur in Hollywood working on big budget productions. Any blockbuster would be lucky to have him in the director's chair. Just my two cents.
EDIT: Also, you guys focus way too much on the tone. You can have a well-crafted film with genuine creative vision and still be lighthearted. Watch 'Raiders Of The Lost Ark', 'ET', 'Punch Drunk Love', 'Annie Hall' and 'The Big Lebowski'. I personally find plenty of aspects of Nolan's trilogy to be lighthearted, Bruce and Alfred's relationship, The Joker is hilarious, Selina Kyle's character and her interaction with Batman ect. Again, my two cents.