Yeah, I may have guessed (correctly?) that TDKR suffered a bit from "sequelitis". The problem with most
film trilogies, despite what the creators say (they're lying if they say otherwise), is that they were NOT conceived as a whole right from the start unless the trilogy is
already based off a seminal piece of a work (ie: LOTR).
A third film almost always often tries to justify itself such that it automatically necessitates it being continuous with the previous movies. This is especially the case when the franchise is slated to be a trilogy but when in reality there was no framework for it in the beginning. One only needs to look at Spidey 3, Godfather 3 and even Return of the Jedi as examples (there are many, many more) of how bogged down they feel because of the unspoken need to "tie-in" with the previous movies. The rare exception to all this in modern times is Matt Damon's Bourne trilogy. I can only hope the
Bourne Legacy can maintain it.
As far as track records go, it seems the the best trilogies are either conceived right from the get-go (with perhaps a little help from source material that was developed over many years by an English professor

) and are really just one giant work like LOTR
or are those that are only loosely connected with each part being powerhouses on their own merits like the Toy Story movies.