I'd rather watch Julia Roberts in an equally duff movie (Mirror, Mirror) pretending, stylishly and wittily, to be a bad mother, or Sigourney Weaver heroically sacrificing in Alien. I'd have happily accepted Helen Mirren in the It's Complicated part - because she has sex appeal, and sex, exploited by the culturally oppressive American family ethos, is really what films like that are about. Arguments about the "ordinary woman" and how she is represented in popular entertainment are specious. Meryl Streep's character in It's Complicated was representative of divorced women over fifty who are lined and flaccid here and there, and also happen to be wealthy and extraordinarily good in the sack. "He'll come back to me because the sex is the best he'll ever get" may prove true but it is a demeaning aspiration.
There's always going to be a neglected or injured demographic. All the audience has the right to demand is suspension of disbelief, not personal wish fulfillment. Michelle Pfeiffer's beauty in Frankie and Johnny was, for many critics, objectionably untrue to the playwright's original intention to tell the story of average people, but an equally true story was created out of it, about how an ordinary woman can be poor and unhappy and beautiful.
French movies, boasting actresses like Deneuve, Baye, Binoche and Marceau, bring off the vagaries and agelessness of sexuality; Anglo-American culture is still uncomfortable with the notion of a moral, sexy older woman, with or without children, and with the idea that beauty, like virtue, is classless, a gift of nature, not to be bought.
Shrek, with its happily matched ogres, who reject the commercialized norm of beauty and end up with mutual reflections, does not untangle the knot of sexual attraction as profoundly as Cocteau's La Belle et La Bête, in which, probably not by directorial design, the beast is so much sexier than the man.