The plan was to make a character as annoying as Jar Jar Binks from Star Wars. It worked. The Jakovosaurs are so annoying that I can hardly stand to watch this episode. If I were grading this episode based on intent, it would get a 10+. But isn't that true of all art forms?
It doesn't necessarily make the episode a bad episode, it just makes it harder and harder to watch each time. There are still many good moments in this episode, so it isn't a total loss.
Overall, the episode is worth watching. It will be an annoying television experience, but it's South Park.