I looked around old posts about this topic, including that really long meta-review by a user here, and the main consensus seems to be that the documentary committed "sins of omission." Specifically, it (1) neglected the role of white supremacy in the casus belli, (2) it didn't reflect women experiences, and (3) it didn't focus enough on Reconstruction. I've also read some of Burn's responses to his critics.
I guess my question is, how could it have been improved? It's a 12 hour documentary, so I'm not sure "sins of omission" makes sense. It seems unreasonable to expect the documentary to include more info that extended its watch time. And while I get the criticism, I do feel like the purpose of pop history is to engage in a form of myth-making. That is, it's impossible and unreasonable to expect the general public to understand topics to the nuance of academic historians, and that necessarily means that a certain narrative agenda must be advanced to incorporate into the national myth, which further necessitates tough decisions on which voices to sideline.
So, what should have Burn's Civil War documentary done differently? Is the issue that it wasn't long enough to incorporate the full story, or is the criticism that the documentary included things it shouldn't have instead of things it should? And if so, what are some examples of things you think should have been removed to make time for the omitted components?
This is a great question. Any answer is going to revolve largely around subjectivity. Too often we read academic book reviews that chastise a book for not being the one "I would write"; instead, one should review a book on the basis of whether is succeeded in being itself.
Documentaries are necessarily efforts at sliming down the subject into a tidy morsel - even a twelve-hour morsel! For the most part, by the way, this is also true of a writing book. I have found that an author who wants to write everything on a subject should probably stick with articles. As soon as one sets off to write a book, it is often a matter of what not to include.
That said, whether writing a book or making a documentary, choices need to be made and things will not be included. Those choices can and likely will precipitate criticism about what should have been included. I see the criticism of his handling of white supremacy as fundamentally more important than that dealing with Reconstruction. If he had included more about Reconstruction, one could take it further and ask why more wasn't included about the twentieth-century legacy of the civil rights movement. One needs parameters.
It has occurred to me watching Burn's Civil War that it reflects his typical preference/prejudice for all things Eastern, neglecting much of what was going on in the Western theater. Of course, he does handle it, but so much of the documentary ends up being about the effort to defeat Lee, and yet the East is Burns's strength and he was wise to stick with his core inspiration. Again, we should be wary of a criticism that focuses on the documentary "I would have made" as opposed to what Burns got wrong.
I have written on what "Burns got wrong" - in this instance, it is about his Mark Twain documentary. Here, we can see that Burns simply gets Twain's Western sojourn wrong. His facts and images are wrong, and his interpretation is flawed. This isn't a question of defensible, legitimate subjectively or of emphasis or what he left out. Getting things wrong is fatal. While I haven't followed all the criticisms of his Civil War documentary, I have not heard that he got it wrong in any significant way.
Could the documentary of Burns have been better. Certainly. To my taste. Could it have been better from the point of view of Burns? Apparently not. I hope Burns would wish that he could remake parts of Twain so it weren't wrong, but changing the emphasis in the Civil War effort is a matter of taste and the legitimate process of subjectivity in interpretation. Anyone who wants a documentary with a different emphasis is free to make one.