The important question about Neil Gaiman's Batman: Whatever Happened to the Caped Crusader? is, does it indeed function as the "last" Batman story? Yes, it does. Gaiman offers in two issues a deconstruction of the elements of a Batman story, what it means for the Batman to die, and how perhaps so many different interpretations of the Batman can coexist. It is a story that will quickly become dated, much as Alan Moore's Whatever Happened to the Man of Tomorrow? has, but that will likely help define Batman for future writers to come.
Whatever Happened to the Caped Crusader? might alternately been called "Batman: This is Your Life." We find Batman present here at his own wake, as allies and enemies recount the story of the death of Batman. Except, each character has a different story of Batman's death, and here the Killing Joke's Joker coexists with the Batman: The Animated Series Joker and a seemingly Golden Age Catwoman.
We find this is not the story of "our" Batman's death -- that is, his apparent Batman RIP/Final Crisis death -- but perhaps the story of "the story of Batman's death," or maybe a story about stories about Batman. Final Crisis plays no overt role here, but there's definite thematic agreement between Caped Crusader and the meta-interpretation of stories in Final Crisis.
Boiled down, the conclusion that Gaiman reaches is that, no matter how Batman dies, he dies fighting. It's true -- I can think of many instances of Batman dying (his un-death in Dark Knight Returns immediately springs to mind), but never a time that Batman gives up. And though it's something one could also say for Superman, Wonder Woman, Spider-Man, and what have you, I think Batman's mortal status gives this a slight edge -- everyone might go down fighting, but Batman goes down fighting and he's "just a man."
Similarly, Gainman whittles down what it takes to make a Batman story such. He tells one imaginary tale where all of Batman's foes are simply actor friends hired by Alfred to humor the mourning Bruce Wayne -- but even this story must by rights include the death of Thomas and Martha Wayne, the presence of Alfred, the Bat-signal, and such. Gaiman closes the story with a terrifically offbeat take on Goodnight Moon where he checks off the requirements for a Batman story -- the Batcave, Alfred, Commissioner Gordon -- and also what might change with time -- "the Boy Wonder" (but not necessarily Dick or Tim); "the Joker and all of you" (the various rogues who come and go). It's a fantastic examination of how to write Batman, and the riff on Goodnight Moon is sweetly bizarre given Batman's status, lets not forget, as the arm-breaking scourge of villainy.
What I found most interesting was the last scene of the book, as the Bat-signal morphs into a pair of hands drawing baby Bruce Wayne from the womb to the world. As Gaiman's Death notes (here in the form of Martha Wayne), Batman's is a backward story -- rather than working hard and receiving his reward at the end of his life, Batman receives his reward first (his time with his parents), and then faces his hard work of being Batman. Only in his death and resurrection does Batman achieve what he otherwise cannot -- the return of his parents -- before he must fight for them once more. It's in this way that Batman's story is different than Superman's, moreso than their powers or secret identities, and bears, I think, additional consideration.
DC Comics pads what would otherwise be a slim volume with a couple of Batman-and-his-foes stories that Gaiman wrote over the years, including a Batman: Black & White story where Batman and the Joker are actors hired to work on the comic book panel. The included origins of Poison Ivy and the Riddler have been many times retconned since their printing; while I understand some readers found these stories to be needless filler, I liked again how they worked with the main story to talk about "stories" -- Batman stories that don't quite fit and don't quite make sense, but which are Batman stories nonetheless.
In twenty years, Whatever Happened to the Caped Crusader? will hardly still be the "last" Batman story. I thrilled to a Jean Paul Valley Azrael cameo in one panel (Andy Kubert does a magnificent job of emulating all sorts of Batman artists), but the presence of Batman's newfound son Damian in seemingly every other crowd scene puts this story firmly in the Grant Morrison Batman era, just as Whatever Happened to the Man of Tomorrow? relates to the Silver Age Superman and not the current. But we currently exit a time when Batman was "grim and gritty" and after that a jerk, and Gaiman offers something else: the Batman who never gave up. If that sticks and defines the Batman to come, nothing wrong with that at all.
[Contains full covers, foreword by Neil Gaiman.]