Wheee! Comics are fun! First Iron Fist and now this! (Actually, I read them in reverse order--Morrison always goes to the top of the stack in my house, are you surprised?)
Batman #666 begins with a Golden Age homage to the origin of Batman, featuring the words "Who He Is and How He Came to Be" just like in that classic Bob Kane story. And because Morrison only has one issue to tell this tale--the story of Damian, the son of Batman, and how he took over as...BATMAN--he dispenses with the origin of this Future Batman in six terse panels and accompanying captions: "When the world's greatest crimefighter and the daughter of the ultimate criminal mastermind got together, there could be only one result" etc etc.
You can see that the tone of these captions recalls the straight-faced hyperbole of old television shows (or radio shows, probably, although I haven't heard any except some of the Lone Ranger episodes and maybe a Shadow excerpt), and by getting the "origin" of Future Batman over with quickly (and he's not called "Future Batman" in the story, obviously, because that would be lame; he's just "Batman"), Morrison can focus on the mood, the action, and the symbolism.
As I've said before and shown, extensively, in an entire book on the subject, Morrison revisits his favorite themes and motifs again and again throughout his career. Batman #666 is no exception, of course. You can see right on that cover image that he's playing with the old-fashioned apocalypse theme with the city on fire, and he's even got his costumed-dude-wearing-a-jacket-or-trenchcoat motif with Future Batman's FUTURE TRENCHCOAT/COSTUME. Nice. But in this case, Morrison seems to be using the apparel not to signify "coolness" as he did with Zenith, or embarrassment (as he did with Animal Man or Cliff Steele), or functionality (as he did with the X-Men), but, instead, he seems to allude to the pulp nature of Batman's origins. This Future Batman looks like an old-fashioned character (he looks very much like the Gotham by Gaslight or Batman/Houdini elseworlds incarnation) because Damian is a classic, old-school Batman. He blows up stuff and punches people first, then does the detective work later. I'm oversimplifying here, but Morrison clearly establishes Future Batman to be very much in alignment, as far as his ruthlessness, with Bob Kane's first year of Batman stories.
Sure, Morrison throws in some Tarot symbolism (the "Hanged Man" on page 8), literary allusions (to Yeats), and some doubling (the Anti-Christ Batman vs. Future Batman), like he usually does, but this story is filled with enough action and brilliant throw-away ideas: the wheelchair-bound Police Commissioner Gordon, Phosphorus Rex, the Hotel Bethlehem, an ape in a clown costume with a submachine gun--to turn the whole thing into a high-speed carnival ride. I love the way he layers the subtextual depth beneath the veneer of a classic super-hero thriller (and finishes it up in a single issue).
It's probably the most accessible and most enjoyable issue of Morrison's Batman yet.
It doesn't matter how this story fits into continuity (answer: it doesn't) or how it relates to the Kingdom: Son of the Bat story by Mark Waid (answer: it doesn't, although I'm sure a comparison would be interesting, but I'm not going to dig that one out of the longboxes tonight). What matters is that Morrison tells a great Future Batman story that illuminates the present.
Just like Brubaker and Fraction used a story of a past Iron Fist to add resonance to the Iron Fist mythology of the current Marvel Universe, Morrison shows us a glimpse into Damian's future to add resonance to the Batman mythology of today.
Batman #666. You don't have to like it, but if you don't then you're wrong. Because it's REAL GOOD.