Having not read every reply in this post, please forgive anything I say that was already said.
The show still hits and misses for me. They still are able to cross that fine line between good "shock" humer, and being mean for the sake of being mean. On the best episodes of South Park, They jump up and down on that line, forcing it to it's boundries where they are about to burst. Since we are on a porn website, let's think of it like this: Matt Parker and Trey Stone are fucking the SHIT out of those jokes.They know, however, that if they come, it might get in the eyes, nose and throat of the home viewer, and a good chunk of those fine people (even some of their most loyal fans) would not enjoy that and turn away from the show. So Matt & Trey Fuck the finest, hottest, juiciest jokes they can write, but at that moment, they must HOLD BACK! We all know (or at least know of) how insanely hard it is to try to pull back at that moment. These guys stop just before the grand moment every episode to keep them from going to far. Episodes like the one with Lucas and Spielberg rapping Indiana Jones and when Cartman let his feelings about Mexicans a the water park known. And let's not forget the dead celebrities on the plane. Just a little bit more, and everyone watching would have a face full of jizz. So after 13 years, South Park still pushes the envolope, and Matt and Trey can make sweet, sweet love to the jokes.