Well, all of his are that way when compared to the typical documentary. Anything he wrote (not just narrated) is superb, and if you compare the percentage of minutes that provide real value, you'll see it much higher than most documentaries. Note: I haven't actually done measurements, but I've watched nearly all of Sir David's originals and many others by other presenters/filmmakers.
The prototypical (actually extreme) example is in the original Life on Earth where he is at the bottom of the grand canyon and says something close to "these rocks are too old to have any fossils" and almost immediately cuts to a new scene where he says "Here in Lake Superior, we have rocks slightly newer, and these show the first fossils!". All the other documentary folks would have bullshit where they say, "so, we need to go to a different place…" and images of travel crap before they get to the point.
The prototypical (actually extreme) example is in the original Life on Earth where he is at the bottom of the grand canyon and says something close to "these rocks are too old to have any fossils" and almost immediately cuts to a new scene where he says "Here in Lake Superior, we have rocks slightly newer, and these show the first fossils!". All the other documentary folks would have bullshit where they say, "so, we need to go to a different place…" and images of travel crap before they get to the point.