It’s entirely possible that “Community” will still be a funny show without Harmon. The cast is talented enough, and the characters delineated enough, that you can imagine a much more straightforward version of the show in which an unlikely group of friends have wacky adventures on a college campus. Given how strange — and expensive — Harmon’s deviations from that formula tended to be, it wouldn’t be surprising if that’s a version of the show that both NBC and Sony would prefer.
I expect Community to be very different. Time will tell whether that’s a good thing or bad.