[10,000 Volt Ghost]

From season 4 onward I think Seth McFarlane lost creative control with his Family Guy It seems like FOX was like "Okay, we'll bring your show back because it makes us money. Oh, by the way. It's OUR show now and we're going to drop references to classic shows and start making 80's references every 3 minutes. Also Family Guy will now be unfunny. Also we're going to change the character types around. New Chris will be old Stewie. New Peter will be old Chris and New Stewie will be just more like a regular kid." and Seth was like "Ooooookay. Well I'm fine with that I guess. Except I get to make a new show and have the characters the way I want them to be. It's going to be like Family Guy + Paul Lynde." and FOX was like "Deal, except you have to have Paul Lynde be an alien and then also have a talking fish for some reason too."

That's my take on it at least.