Well, to be fair, some have argued vehemently on here that Batman should not be portrayed as a legacy character ever and that it betrays the core of the character.
To me, TDKR's ending was just as fitting as DKReturn's was for that story. The trilogy centered around the power of symbols, the idea of Batman being more than just a man, getting people to rise up and not be afraid, etc. Blake is a symbol for "the common people" of Gotham answering the call.
You say so what that he sets up a legacy? I say it's a pretty fitting ending for this particular incarnation of the character. You're acting like he's fulfilling his butler's dream just as some sort of superfluous favor. You're forgetting the whole point of the movie- that he regains the will to live through relearning to fear death. He regained some of that basic humanity and is able to move on with is life, rather than die an early death. Oh yeah, and that "butler" is the closest thing he has to a father. So making him happy and proud is pretty damn awesome too.
The only criticism I could see with that is that it makes Bruce seem "soft" or something. But that's kind of the whole point. He decides to enjoy what he has left of his life, and he makes the decision to trust one of "the people" to carry on his work. I'm so glad that Bale's Bruce won't end up like the washed up, bitter old man we see in BEYOND.
...cue you saying Selina gets hit by a bus and Bruce decides to become a transvestite.