Richard Schickel spelled out his own disappointment in the opening paragraph of his review in Time Magazine:
"A schlemiel may be, must be, grievously acted upon by the always malevolent world. But he can never be permitted to act effectively against that world. At the end of his adventures he must, somehow, triumph over the forces of darkness that surround him - but only accidentally so...In that spirit of genial fantasy, we permit out surrogate that utter self-confidence, that sublime sangfroid, with which with he cheerfully motors his way around and through disaster."
I suspect Schickel is alluding here to what critic James Agee, his predecessor at Time, described as "the principle of the brick". The principle comes from Frank Capra, who, as a silent comedy writer, used to write for the silent comedian Harry Langdon. According to Capra, Langdon's "only ally was God. Langdon might be saved by the brick falling on the cop, but it was verboten that he in any way motivate the brick's fall." The new Get Smart, deciding to make Agent 86 an ineptster suffering from an inner fat kid, makes him proactive in that old dreary screenwriting 101 way by having him learn his craft on the job until he triumphs.
Adams' Smart, by contrast, made it through 5 years in the role on TV through the blustering, sublime self-confidence of a man who was certain he was ahead of every plot twist ("Ah, the old false lips trick..."). Adams' Maxwell Smart knew God was going to drop that necessary brick when the time came.
The missing spy movie fatuousness in Get Smart (2008) was all over this year's best satire of the genre, a 2006 French import titled OSS 117: Cairo, Nest of Spies which finally got an art house release this spring. That French film trafficked in Don Adams' version of unshakable idiot debonairness. True, Jean Dujardin's Agent OSS 117 did throw the occasional brick, but he was more frequently hit by them. Have a look if you can, compare and contrast, and say which works better as a comedy...