Firefly gets mentioned a lot, but there are a few of reasons why I wouldn't want to see it come back.
1. Wash is dead.
Ok, that's not a few.
Also, the 14 episodes and 1 movie we did get just seem to be the perfect amount. Sure, you can say, "I'd love to see more." But are you really unhappy with what you do have? There wasn't a cliffhanger. River is no longer crazy. Mal and Inara's relationship will always be complicated. Simon and Kaylee are happy. Jayne has his guns and Zoe has her sense of loyalty to Mal.
This way, there is no Jump the Shark moment.