For me and for most Americans there is nothing more interesting than the story of the West. From the Civil War until World War 1, the West was full of adventure, opportunity, drama and tragedy. AMCs series "Hell on Wheels" was an excellent attempt to portray one aspect of this period, the building of the railroads. But their far more ambitious "The American West" is a big disappointment on a number of levels.
For a documentary, the use of "expert" opinion from movie stars is hardly a good idea. Have we stooped so low that we get our history from movie stars?
Perhaps the reliance on movie stars for the primary documentation is one of the reasons this 8 part series has so many errors (e.g., Jesse James and Billy the Kid met, Wyatt Earp went to Tombstone to be their Sheriff).
Another weakness of the series is that there is no real underlying theme. There are brief episodes about Jesse James (Missouri), Billy the Kid (New Mexico), Wyatt Earp (Kansa and Arizona), and Custer and Sitting Bull (the Dakotas). But there is no real glue that holds the episodes together (e.g., the demands of capitalism to obtain natural resources, the political post war climate, the economic problems and the challenges of currency, etc.)
Telling the story of the West is an important project, but this series fails to do it in a meaningful way. FWIW - I really like the TV series "Centennial" (1978-79) and "Hell on Wheels" (2011-16). They both gave a comprehensive history of the West and did so in a more entertaining manner. For sheer pleasure, "Pat Garrett and Billy the Kid" (1973) is my favorite telling of this story.