How is South Park done right and Family Guy done wrong?
It's better written, endlessly more original, has more regard for plot and actual messages. When South Park does a parody/critique they mostly raise valid points about whatever it is they're criticizing. When they do shock stuff it works on a higher level. Cartman alone is a better character than the entire cast of both Family Guy and American Dad combined. They're just... cleverer. It's really that simple. Disagree if you like. The best Family Guy episode I've ever watched was the parody one in South Park, it's just so dead-on.
It used to be much more clever in its golden days
I've seen the whole first season and found it pretty watchable and funny, if really inconsequential (to be fair, so was the first season of South Park, and the first season of The Simpsons was even worse), but the recent stuff I've watched just makes me ashamed.