I was only mildly surprised by the renewal. As I wrote earlier in this thread, why fire the showrunner of a show that you know is only going to on one more season. Makes no sense. The other big hint was that they called the last episode the "season finale" rather than the "series finale". The ratings may be rather minuscule but NBC must love the demographic that makes up those ratings.
Even without Dan Harmon, I am ecstatic about finally seeing a season (or half season) without Chevy. Hopefully, the showrunner will use this extra time to get further acclimated to the characters. I'm also hoping (and this is surely a pipe dream) that Jim Rash is promoted to producer with more a voice in storylines. Also hoping he does more writing. Very satisfied with this news.