George, GOB, Tobias, Cox, and others are FUNNIER than the main characters, and thus can be your favorite character or the most interesting, but without the main characters of their respective shows, they start to fall apart. For Seinfeld and AD, they need their "straight" man, and for Scrubs the entire fucking show is JD's story.
A show like Community is a true ensemble cast, so no character really gets more shine than any other and they bounce off each other.
But... I just started watching Parks and Recreation, skipped Season 1 and watched most of Season 2, and it is definitely this show. I love Leslie, I think she is HILARIOUS, but all of the supporting cast kills it. Leslie has a great dynamic with everyone but there is so much chemistry between Ron, Andy, April, and Tom that the show COULD, conceivably, be a good show without Leslie. Maybe not as good, but it wouldn't suffer like many other shows would.
I only like good shows (lol) so I can't imagine any of them without their lead actor, because if the lead actor isn't well written, then who else would be? What IS the show?
Edit - At the above... come the FUCK on. Leon is funny but Larry is one of the best EVER, if not the best, in my opinion. That is so ridiculous.