It doesn't matter who will write it, the movie is the same as the show. From what I know of the preview, the movie will have prolonged one liners and idiotic facial expressions. If the movie was made in the 90's, it could have been genius as a TV to Film translation.

I'm not a Family Guy or South Park fanboy, even now those shows such almost as much as the simpsons. I loved each of these shows but now they have gradually descended into idiocy. They all have the same plotline, bad jokes one after another. Watch each of the classics of these shows and then the later ones and realise that something has changed.