TV's Gunsmoke, to me, has three eras: the Half Hour Era, (the first 6 seasons), the Hour Black and White ERA, (seasons 7-11) and the Color Era, (seasons 12-20). The most popular era, both in the ratings and with Gunsmoke fans, is the first era. The shows were TV versions of the best episodes from the radio series. With only a half hour to tell their story, the scripts were lean and to the point. The actors were as young as their characters. And black and white seems to fit the rather dark morality plays the series specialized in. The show reached #1 in the ratings the last four years of that era. It's "classic Gunsmoke".
When they went to an hour, in the minds of a lot of fans, the stories became bloated and were written by new writers who focused less on the main characters and the quality of the show declined. This seems to be confirmed by the ratings, which declined to 3rd, 10th, 20th and eventually to 36th when the show was canceled before William Paley, the CBS chairman, ordered it put back on the schedule and, in the color era, it had a miracle comeback all the way to #2 by 1969. That makes the Hour Black and White Era the apparent nadir of the show.
I beg to differ. Part of it is that, being born in 1953, the Hour Black and White Era is the Gunsmoke I grew up with. I prefer the black and white episodes to the color ones because the color seems to emphasize the studio-bound nature of the Dodge City set and the increasing age of the actors. Also, magazine photographers have always had a saying that you use color for excitement and black and white for drama: Gunsmoke is a drama. And I like the hour episodes more than the black and whites. I don't see the stories as bloated at all. I see them as developed to their full potential. The focus on the "guest characters" opens up all kinds of dramatic possibilities. And there are actually more episodes that focus on the regular characters in greater depth than most of the the half hour episodes were able to do, (such as the upcoming "Chesterland")
"All That" is a great example of how the series actually improved during this period. It stars John Larch, who was in several Gunsmoke episodes, including the first season "Smoking out the Nolans", in which he played a prosperous rancher who wants to evict an less fortunate family from the small ranch they were leasing from him. Here Larch plays the unfortunate farmer who loses his wife to another man, his ranch to a creditor and most of the value of his livestock to a shifty agent. In half hour episode, the story might have ended there. Instead he goes to Colorado, is again a failure at prospecting but then comes up with a scheme that combines elements of Mark Twain's "The Million Pound Bank Note" and Molière's "The Imaginary Invalid". The result is a most satisfying concoction, one that could not possibly have been done in a half hour format. There are many other such episodes in this period.
So, why did the ratings decline if the stories actually got better? One reason might be that Saturday night is a mobile time period, historically a ratings dead zone where sporting events do better than dramatic TV shows and an hour show might not fit into people's schedules as well as a half hour show with a simpler plot. or maybe it was because NBC started showing recent blockbuster films on it's "Saturday Night a the Movies" in the fall of 1961 for stay-at homes. Maybe both. But it surely wasn't the fault of what was actually the new and improved hour long "Gunsmoke".