Actually I just read an article regarding the pulling of South Park and Isaac Hayes quitting. What I got from it was that Isaac Hayes couldnt' have quit because he was in the hospital when the episode aired the first time, last November or December. In fact, when Hayes came out he was on record for saying he enjoyed the episode, I think for some late night talk show, I forget which one. Either way, I don't see Hayes really wanting to quit/being fired after being on the show so long. And besides, he hasn't done too much the last few seasons.