The same issue is happening on a show like Everybody Loves Raymond now, which is in its eighth year and struggling to come up with good stories. It'll be interesting to see how they do. The bottom line is, it starts with the writers and ends with the writers.
“I do not hesitate to say that the limitation on naval craft between the great naval powers was too high.”
“An agent said he didn't know what to do with me, I wouldn't be able to play any parts but lesbians and aliens.”