dir: Shane Black
Third-parters are almost never good. They never work out well, whether in comparison to the first two instalments, or compared to any other decent films in general. Aliens III? Matrix: Revolutions? Superman III? Can you think of a third parter at least as good as what came before it? The only one I can think of is Return of the King, which many callous people think of as being The Kiwi Flick with Three Hours of Endings. But I don't, since if one happy ending is a good thing, then lots of happy endings has got to be even more super amazing.
You could argue that the difference is when the third part of a film trilogy is an organic part of the story, rather than a second sequel, whose purpose is just to capitalise on diminishing returns. Where Dark Knight Rises fits into this I couldn't tell you. Where some would argue 'necessity', others would argue 'doesn't say anything it hasn't already said twice before'. So whether it's Shrek the Third or Jaws III or Robocop III, or Spider-Man III, we're generally programmed to expect much more of 'more of the same' -ness to predominate, as well as a certain tiredness to the premise and mistakes particular to thirds that just have to be made.