I still enjoy "The Simpsons" a lot, but I do agree that on average it's not as good as it was 10 years ago.
"South Park" however, is better now than it was early on, mostly because of how satire based it now is. The South Park movie is amazing, but I', sure that if they made another it would be just as good.
Anyway, looking forward to this movie, it's been in preproduction for a long while now so here's hoping they've got a good script, just still a huge shame it couldn't have been made during Phil Hartman's lifetime.