Comedy Central was right to cancel Futurama. It was not going anywhere. The stories were becoming stale, and it was time to make room for some new shows. At some point and time, everything must come to an end. It was time to say, "out with the old and in with the new." We are not missing much. In fact, we may gain a few brain cells.
I grew up watching Futurama and even though my opinion may be biased, it was great comedic way to express life in the future with aliens, robots, and unbelievable machinery. Watching Futurama would most likely bring a smile to your face whenever in a bad mood. Me along with many other Futurama fans were disappointed.
It's a show that a lot of people love, and it has a rather dedicated fanbase. It has become an icon. There are a lot of people out there who want to see it keep going and who still want to support it. If people still want to see it and the creators still want to make it, let it live.
Keeping Futurama around could have only been a positive thing for Comedy Central. First, the show was still making them money, which is the prime goal of the network. Second, there were clearly still people who enjoyed the show and even for those who didn't anymore, its continuation could not have affected them negatively. It would have been a win-win.