Have we really seen the last of Michael Bay’s Transformers? The runaway success of the franchise, which has long raised its middle finger at our collective intelligence, would seem to suggest otherwise, but if Dark of the Moon is the final chapter of this inane trilogy, it is also the least insulting.

Its title an acknowledged nod to Pink Floyd’s classic 1972 album – expect Captain America: Born in the U.S.A. sometime soon – Moon is the most visually coherent entry in the Transformers saga, and for a merchandising juggernaut designed to appeal more to the eyes than the intellect, that’s a small but significant victory.

Perhaps the most curious aspect of the series’ box-office supremacy is how utterly pedestrian the Transformers look. CGI creations phony to the point of distraction, they resemble towering piles of industrial junk. In battle mode, as they so often are, they are mostly indistinguishable from one another, so much scrap metal crashing together in a bewildering maelstrom.

Moon offers no improvement in that regard, but Bay’s flair for spectacle is evident in his skillful use of 3-D and in his convincing deconstruction of downtown Chicago. (Hotel 71 will never be the same.) The mayhem unfolds predictably, but with a clarity missing from previous Transformers installments.

At 22 minutes, the original Transformers cartoons – launched in 1985 after the FCC eased restrictions on toymakers seeking to broadcast episodic ads for their products – were short enough to sustain even the slightest conceit.

At precisely seven times that length, Moon is a weightless work of almost perverse self-importance, made worse by its flag-waving appeal to patriotism and its too-casual evocations of 9/11. Bay frames the conflict between the freedom-loving Autobots and their rival Decepticons as an allegory for America’s War on Terror, and though his shamelessness is hardly surprising, it is borderline offensive all the same.

Lest we forget the human caricatures in this ludicrous drama, they are dutifully played by series mainstays Shia LaBeouf, Josh Duhamel and John Turturro. Bay has also assembled a formidable cast of newcomers, including John Malkovich, Frances McDormand and a delightfully slimy Patrick Dempsey, who breathe intermittent life into Ehren Kruger’s perfunctory screenplay.

As for the plot, it suffices to say that mankind’s fate once again hangs in the balance, giving Victoria’s Secret model Rosie Huntington-Whiteley ample reason to pout. She does so as effectively as Megan Fox, whom she replaced in an eye-candy role that is a winking concession to the 12-year-old boys who will likely make Moon the year’s most profitable toy commercial.