This visualization of the class differences is the most obvious difference and contribution of this film. This makes the material stakes clearer---the Bennet girls don't need to marry into the gentry (they aren't golddiggers or social climbers), but just to stay at their present level, since their home and lands will go to a male relative according to the law.
But there are also noteworthy and interesting differences in narrative and character shadings. Though keeping some of Austen's references to the ages of the sisters (the oldest in her late 20s), this film portrays them as younger, especially Keira Knightley as the heroine, Lizzie Bennet. She is bright and witty, but no Greer Garson. She seems more like a mischevious 20 at the oldest, trembling with girlish energy. This actually works to make plausible the idea that she's considered the less attractive sister. When she wrinkles up her nose, giggles and ducks her head, having fun with her sisters, it's plausible that her beauty, so evident in repose, would go unnoticed.
Her "more beautiful" older sister, Jane (Rosamund Pike) is evidently beautiful, and is seen much more in repose. What makes this film work immediately is how perfectly matched she is with Simon Wood's Mr. Bingley. Both are shy, modest and sincere, and seem out of place except with each other. They are also both blond. It takes the dark-haired Elizabeth and dark-haired Darcy awhile to discover the secret of their darkness: though both are flawed with pride and prejudice, they share a fierce moral rectitude not at all incompatible with physically passionate natures.
As for this film's take on Darcy, I endorse Stephen Holden's description in his New York Times review (this time in contrast not with Olivier but Colin Firth's portrayal on the 1990s miniseries):Mr. Firth might have been far more dashing, but Mr. Macfadyen's portrayal of the character as a shy, awkward suitor whose seeming arrogance camouflages insecurity and deep sensitivity is more realistic. Isolated by his wealth, ethical high-mindedness and fierce critical intelligence, Mr. Darcy is as stubborn in his idealism as Elizabeth is in hers. The disparity between his diffidence and her forthrightness makes the lovers' failure to connect more than a delaying tactic to keep the story churning forward; it's a touching tale of misread signals.
This is the first major film by director Joe Wright, and it has the studied innocence and ambition of a first movie. Somebody will no doubt study the significance of the many appearances of flame, and how they dissolve into something else. There are plenty of references to other films, especially Olivier's more famous romantic role in Wuthering Heights. But he has so much visual energy (with a score that suggests Philip Glass playing appropriate bits from classical composers, and I say that with admiration) that the symbolism of Lizzie whirling on a swing when she's confused is not at all heavy-handed because it's so deftly done and neat to look at.
He and the screenplay author (Deborah Moggach) also deliver some subtle scenes and dialogue that illuminate minor characters, in place of the delightful movie caricatures,of 1940, particularly Sutherland's Mr. Bennet. Brenda Blethyn's shrill and frenetic Mrs. Bennet also gets some sympathetic moments, when she makes clear what she's up against, that the necessity of five daughters marrying decently if not exceptionally well is no joke, in an age and place that could condemn them to the most degrading circumstances Dickens presented. (This couldn't have been an easy script to write either, as the story seems to defy Hollywood's preferred simple three-act structure.)
In the last part of the movie, realism is perhaps stretched to accomodate the romance, but the film has earned some indulgence. Perhaps someday I'll put together my own double feature of these two Prides and Prejudices. Maybe next New Year's Eve.