You have to admit that when you’re doing a sequel to, or perhaps more accurately a reboot of, Steven Soderbergh’s three modern “Ocean’s” heist movies (2001-2007), it takes chutzpah to focus on a caper that involves replacing a priceless necklace with a chintzy knock-off. Yet that’s precisely what Gary Ross and his co-writer Olivia Milch have done with “Ocean’s 8.” Not that Soderbergh’s movies were particularly good—the first was okay, the two that followed pretty bad—but they were popular, and so for an expectant audience the stakes are pretty high, and joking about cheap imitations might easily invite snarky comment.

In the event, however, Ross’ movie, while flatly directed (and languidly edited, by Juliette Welfling), isn’t appreciably worse that “Ocean’s 12” and “Ocean’s 13.” It too has glamour, and a plot that strains to seem ingenious and surprising. But also like them it’s much less clever than it hopes to be, its humor is forced and smug, and it runs on at the end. It also fails to use its cast to best advantage.

A major point of interest, of course, is the gender-reversal at the heart of the movie, an idea that’s actually a promising one. But if the remake of “Ghostbusters” should have taught Hollywood anything, it was that in making a feminine-centered version of an old hit, it’s not enough simply to assemble a cadre of talented women; one also needs a good script and skillful direction. “Ocean’s 8,” unfortunately, doesn’t exhibit enough of either.

The instigator of the larcenous plot is Debbie Ocean (Sandra Bullock), the estranged sister of the supposedly deceased Danny, whom George Clooney played in the previous movies. Up for parole after serving time for a heist actually committed by her then-boyfriend Claude Becker (Richard Armitage), she talks her way out of prison with honeyed words about going straight and then scams her way into a room at a posh hotel, scooping up some free items at Bergdorf Goodman on the way. Then she hooks up with her old partner in crime Lou (Cate Blanchett) to enlist her in a big score she’s been planning during her years inside: the theft of a $150,000,000 diamond necklace kept in the Cartier vault.

To pull off the heist, the two enlist the services of an idiosyncratic crew: Amita (Mindy Kaling), a gem expert; Tammy (Sarah Paulson), an experienced big-time fence turned suburban mom; Constance (Awkwafina), a sleight-of-hand expert; and Nine Ball (Rihanna), a brilliant computer hacker. But the key to the plot is Rose Weil (Helena Bonham Carter), a goofy has-been fashion designer whom Debbie wins over by arranging for her to make the dress to be worn at the Metropolitan Museum’s star-studded gala by the affair’s prima donna celebrity hostess Daphne Kluger (Anne Hathaway). Weil is tasked with insisting that the only accessory that will go with the gown is the Cartier necklace, and once it’s at the event, the team will engage in complicated maneuvers to relieve Kluger of the piece and sneak it past the heavy security, substituting a zircon replica in its place.

As a bonus, Debbie arranges that Daphne’s date for the evening will be none other than Becker, whom she intends to frame as the fall guy this time around. Of course, things don’t go precisely as planned as the scheme works itself out, and a degree of improvisation is required along the way. Are the girls up to the task? What do you think?

The one thing the movie has in abundance is glitz, thanks to that Met setting (and some of the other New York locales); the production design by Alex DiGerlando, set decoration by Rena De Angelo and costume design by Sarah Edwards are all aces, and Eigil Bryld’s cinematography adds lushness to the images.

When one turns to the actual heist mechanics, however, matters are much less rosy. The plan is complicated, but based less on skill and smarts than technology and drugs, whether it be a computer program that duplicates the necklace from afar or some sort of brew that causes massive diarrhea. As for the hiccups that happen when the plan is put in motion, they’re handled remarkably easily; one last-minute hitch is resolved by a quick phone call by Nine Ball to her sister, who happens to be a genius, too. That’s not so much a case of cleverness as of lazy screenwriting.

Nor do Ross and Milch manage to give their characters a lot of…well, character, and as a result most of the cast are not shown at their best. Bullock pretty much sails through the picture with a brittle smile; she wears her elegant wardrobe with aplomb, but brings little charm to the party, apart from her opening parole-hearing scene. Blanchett fares even worse; her stern demeanor seems designed for a different movie altogether. Kaling is surprisingly nondescript, and so are Paulson and Rihanna, while Awkwafina is used as a one-note comic relief figure.

The two stars who stand out from the pallid pack are Bonham Carter, whose pose of befuddlement is amusing, and Hathaway, who goes for broke as the ditzy diva who’s the gang’s primary mark and scores a bullseye. Armitage is a bore as Bullock’s unchivalrous ex, but James Corden earns some laughs with his turn as a frazzled insurance investigator, livening up the long post-heist coda that is otherwise pretty anemic.

There’s nothing wrong with “Ocean’s 8” that a shot of cinematic adrenaline wouldn’t have fixed—the sort of verve that Soderbergh, for example, brought to last year’s “Logan Lucky.” Unfortunately, Ross wasn’t the man to provide it, and as a result the movie is at most a mildly engaging time-killer that few will rate as a ten.