NO NO NO NO NO NO . i'm fine with the short films, and the TV Specials (first TV Special comes Oct. 2013) but Pixar should stay away from sequels after Monsters University.
I don't think any of the pre-Good Dinosaur movies (Pixar's 2014 film) should have sequels, except for The Incredibles. The Incredibles sequel is inevitable, a Pixar employee that taught me told me that Brad Bird (director) will have it done one day and is thinking ideas. Incredibles sequel won't be bad, cause the story of the family still has more to be continued.