>>96299006I think it's way easier than this, the thing is... Family Guy doesn't have characters. Each individual on the show is just made as broad and blank as possible so that they can all occasionally support whichever joke the writers decide they want to do. They aren't developed, they are the opposite of that, and it's done on purpose.
For example, Stewie is usually the butt of gay jokes, but the show doesn't shy away from throwing them at... just about everybody in general. So then, if gayness isn't something that defines Stewie, what is? And he in particular doesn't suffer much from this because he does have things only he can do and say that make him an actual character, but this isn't the case with just about everyone else. What's something only Meg would say? What about Chris? Peter? Lois? They've got nothing unique, and it's so that if the writers think of a joke, they don't have to limit themselves to one character.
I've read the interview MacFarlane did where he explains why they just won't confirm that Stewie's gay even though he himself believes so. Want to know why? It's so that if they want to still make a plot or joke that involves Stewie doing something heterosexual they can, they keep every possible door open but in doing so every single character is just nothing, not unique at all.
Now look at cartman, and you see that there's plenty of things only HE can and would do in South Park. Same goes for everybody, they're well defined and the plot is based around them, not the contrary which is true for Family Guy.
So tl;dr:
Family Guy bases their characters around the plot.
South Park bases their plots around the characters.
And the second formula works way better for getting attached to characters and building clever dynamics that in and of themselves can make for funny situations that are impossible otherwise.
