Your specific comments about the audio production sound right to me.
I would add that this production demonstrates that everybody -- even Ken Burns -- needs an editor. I don't have any objection at all to framing the film in terms of the four communities. But at times -- especially as each of these first two episodes began -- Burns seemed almost to be stretching to fill the time. I think it happens sometimes that when a filmmaker has profound subject matter but not quite the film to do it full justice, he becomes ponderous as a way of trying to convey the significance of it all.
“...he becomes ponderous as a way of trying to convey the significance of it all.”
Yes, precisely. ...Well put.