Cartoon Network's Rick and Morty, with its massive viewership and critical acclaim, is probably the standard bearer for TV animation right now. But as co-creator Dan Harmon recently pointed out to me at a press event in Los Angeles, only 21 episodes have aired so far, and that's not all that much material to evaluate from.
The show's fan community grew massively during its nearly two-year hiatus, and, according to Harmon, "It wasn't because we were like pumping out episodes. It happened while we were still taking too long on season 3. It just grew by itself."