Family Guy used to have me rofl every episode, and these days it's a miracle if i even chuckle during a single episode. They also keep relying on their old jokes a lot more lately, most of which were never funny.
Like Peter tripping and holding his knee and saying 'AAAhhhhh' over and over..... yeah that wasn't funny. It wasn't funny during the Chocolate Factory parody, it wasn't funny during the A-Team parody, and it wasn't funny when Lois tripped and hurt her breast either.
Or the two 30's entertainers with the piano. They lasted 6 or 7 seasons and were never actually funny from the first time they appeared. Stewie kills them in one episode stating that they won't be back (acknowledging that fans don't find them funny), and low and behold they've been used again since.
Consuela was funny when she was Superman's maid, but after that she's never been remotely amusing. Sorry, but quitely saying 'No, no, i clean' repeatedly does not amuse me.
Saying that though, American Dad has its flaws as well. It now seems as though every story has to revolve around Stan and Roger, and fuck everyone else. I'm also getting sick of Stan going to talk to someone, buy something or achieve something, and everytime he meets the guy it turns out to be Roger in disguise...... EVERY TIME!
Klaus, the German fish, is probably one of the best elements of that show, and if he gets more than 2 lines an episode now it's a fuckin miracle, and i have to say Hayley has become so irrelevant she may as well not even be there anymore.
When American Dad first came along, i thought it was just as good as Family Guy. Now i'd say Family Guy is the better of the two, but both have gotten worse in the long term. However, both are still miles superior to the Cleveland Show, so..........
And American Dad having Patrick Stewart is far better than Family Guy having Adam West.