The last and so far only episode he wrote for on that show was Space Pilot 3000. Matt just has a lot of control over both shows, and aside from creating the main characters has not put much creative effort in either show. I do have an enormous amount of respect for Matt, but sometimes you have to dish out criticism were it is due.
I'll feel the same way. Truthfully, I'll feel pretty much indifferent when shows like Family Guy or South Park end, even though I've spent many years watching those shows, but when The Simpsons ends it will be different. That show is and always has been my favorite show, despite it's problems. That show has been around almost as long as I have, and while there have been other shows that I loved to death, they all came and went, whereas The Simpsons has always been there.