Substitution
Deacon Blues
I've got one better: Ditch Sparky.Sort of. The show itself started in like 2001. I used to like it. But it jumped the shark more times than Sponge Bob and the Simpsons. Which is quite a feat, since it hasn't been around as long.
To be honest, I don't think long running series are a problem. At the worst, you'd just need to change a few writers if need be.
That alone is a step up.