In the episode "The Blue Harvest" (FAMILY GUY's parody of STAR WARS IV), Meg's likeness was relegated to 'that worm in that asteroid' while her two brothers got to be Luke Skywalker & Darth Vader! Cry "Havoc!" & Loose the Hounds of War! Shouldn't FAMILY GUY's producers put out a special parody in which Meg's image plays ALL the parts?
Meg is the loser of the show and the butt of all the jokes. I'm not saying it's right, that's just the way it is. In a family of sarcastic people, all of them have been the butt of a joke at one point or another. Meg is the least dynamic and exciting character. She doesn't have much of a personality and she unfortunately resembles Peter, not Lois the ex-model.
Family Guy cuts close to the bone, I remember the very first episode I saw, Peter said that Sarah Jessica Parker's face looked like a FOOT! I was like woooah, that is soooo cruel, but of course from that moment I was IN. Some of the things they say on the show are truly shocking, but I believe it's mostly to cut other celebrities down a peg, so they don't take themselves too seriously, specially the ones who have an obvious sense of self-importance.