Rotten Tomatoes has interviewed Brad Bird briefly about taking over Ratatouille and what kind of changes he made and what he kept the same. He even mentions, without naming it, 1906.
The Associated Press via The Washington Post has a good article on why Pixar, despite all the advanced wizardry techniques in animation and digital rendering, always comes back to "old-fashionedness". On The Simpsons animators comes this quote from Brad Bird…
"I started pushing the storyboard artists, many of whom had trained on Saturday morning animation, to think of each episode as a movie, and to look toward Hitchcock, Welles, Kubrick and Scorsese for inspiration rather than other animation,"
Have a read here.
Also, Teddy Blanks from notcoming.com has a nice article on how Pixar continues to set the bar in animation and overcomes the hurdles of computer animation.