Monika Bartyzel has an excellent and insightful essay on Movies.com called Girls on Film: Why Supporting Female Characters Matter.

Funny men like Seth Rogen and Jason Segal act as the everyman with a witty sarcastic edge, and since men dominate cinematic comedy, this relatability is front-and-center. But these are male-dominated characteristics that have no realistic female balance or counterpoint. They can offer relatable aspects, but not a comedic mirror for the female audience – women relating women. Since men almost universally take the lead in any comedic film that doesn’t start with “rom,” women must turn to the supporting roles – roles which are not only secondary characterizations, but also clichéd whirlwinds that have little resemblance to reality.

She used twitter to invite comments and heard back from women who were also concerned about the portrayal of female characters:

Most complaints centered on one of the most prevalent characterizations – the shrew – the woman who acts as the anti-fun counterpoint to the fun-loving man, who, as smart as she may be, cannot lighten up, who has no sense of humor and takes the fun away, and sometimes needs the man to teach her to lighten up and live. Other irksome qualities included women with a lack of friends, women as either asexual or ridiculously sexual, clingy partners, unreasonable man-haters, catfighters, superficial characters, bossy beasts, hormonal time bombs, and lest we forget – jealous, green-eyed monsters who will not allow men to interact with any woman who is not a blood relative.