The L's Benjamin Strong thinks it does (as do I), which explains, really, why for him, "Storytelling has never been Cameron's strong suit," whereas for the WOWed Dargis, "He’s a masterly storyteller."
The reason why Avatar permits these two seemingly incompatible readings has to do with cinema-as-spectacle.
In the same sentence, Dargis also allows that Cameron is "a rather less nimble prose writer," citing the hero "taunt[ing] a rhinolike creature" with a "Yeah, who's bad," which I think we can all agree is no "Fuck you, asshole," let alone "Hasta la vista, baby," as far as dialogue-by-baddass-preadolescent-catchphrase goes.
Cameron's two-fisted tales and comic-book dialogue are matched with a fairly elemental narrative about a young man choosing between two parents (the scientist played by Sigourney Weaver and the mercenary played by Stephen Lang); or the narrative's about a young man leaving the world he knows and finding love, adventure and his own place in another tribe; or it's about a messianic leader who comes to lead an afflicted tribe. In all cases it's some real hero's-journey shit, so if you think Cameron is a transcendent visual worldmaker, then all the classical story, corny dialogue and rousing speeches become, well, Pure Storytelling, with archetypal character types and scenes and dialogue capable of consolidating a whole culture, like how Joseph Campbell is always going on about Star Wars and Jung.
(One might point out Avatar's virgin's secret awe of sex, and recall Terminator 2, in which the fans of the first movie had all their fantasies and tastes validated by an epic narrative, and conclude that Cameron's sensibility is too stuck in adolescence to be truly transcendent pulp. But let's proceed a little longer under the stipulation that it works in the way he wants it to.)
Of course Cameron knows all that, about archetypes, and is, like Lucas and Spielberg and all those soppy-hearted dumbdowners, far more self-conscious of his mythic material than most of the mythmakers he grew up loving. (His self-cultivated legend for outsized storytelling tends to reinforce this assumption.) He takes it upon himself to be The One to show the world the latent grandeur of our pulp stories.
It's not, I don't suppose, a bad thing, in the historical longview, that Cameron is a hubristic, self-aggrandizing filmmaker, any more than it's a bad thing that like D.W. Griffith was. No, the problem is that Avatar is a self-aggrandizing film.
Cameron's hero, an ex-Marine, ultimately sides with the oppressed native people against the imperialist American energy concern and its private security force, some kind of hybrid Native American jihad. Though, as the L's Strong says, "it's hard to entertain seriously the proposition that the Most Expensive Movie Ever is on the side of the underdogs."
But aside from the intractable disingenuousness of a movie from which Rupert Murdoch stands to profit casting its lot with the insurgency, there's the matter of why exactly Cameron does this. By all accounts he's a good liberal—albeit one who probably jerks off to Lara Croft and is obsessed with firearms—and he makes pretty explict Avatar's anti-Bush subtext. But Avatar doesn't play out the way it does because Cameron has subversive political views: it's less concerned with the cause of the underdogs than it is with the agent of their improbable deliverance.
Cameron's identification with his protagonist—his on-screen avatar, like him a macho explorer of unknown realms—is evident. And then this hero becomes the Great White Hope for Avatar's blue people—as did, many have pointed out, the character played by Kevin Costner in Kevin Costner's three-hour film Dances with Wolves. Cameron's identification with the underdog isn't political, it's personal—Goliath's side isn't in need of a savior.
Avatar's existence, and success, primarily serves to reflect glory on James Cameron. Which, again, is fine. But its story does so as well, by hinging on the lone hero who arrives in time to do the impossible. In her review, The Dargis refers to Titanic as a "megamelodrama," which I initially read as "megalodrama." That sounds about right for Avatar, actually.