The Ambersons Laserdisc is most interesting IMO for the fact that it includes the script, stills from the cut scenes and Carringer telling us where a scene was supposed to go before it was cut. I agree that Carringer sounds "dull", but most commentary tracks, IMO are for beginners. Those of us who are Welles fans, who have read about the films of Welles since their college days at least (that would be mid-seventies for me) "don't need no stinking commentary track"!
If it is not the director of the film commenting, or if it is not an obscure film that needs a lot of commentary, the commentary falls flat. An ideal commentary is found on Criterion's Laserdisc of The Life and Death of Colonel Blimp. This is not a well-known film to most people, and Martin Scorsese reveals how the film inspired him as an aspiring filmmmaker. Then, the film's director, Michael Powell, provides his thoughts. I find it quite moving to hear Powell, barely alive, describe what he was going for in certain scenes, and then still be moved by some of the scenes. One of my favorite moments in Blimp, with or without commentary, is the scene between Roger Livesey and Deborah Kerr after Livesey has invited his German friend, Anton Walbrook to dinner. This is Kerr's last scene in the film as Livesey's wife (remember-she plays three (!) parts in this film), and Powell says "this is one of my favorite scenes. What a wonderful way to say goodbye to her". Then, as Livesey kisses her hand, Powell is a bit overcome with emotion as he says "Oh, dear".
Kerr does not die there. A montage of headlines aids in the passage of time before it is revealed that Livesey has suffered "an irreberable loss". But Powell knew this would be her last scene, and it was structured as a kind of goodbye to her. Now, when I watch the scene, it moves me in all kinds of ways. For one-every time I see a film in which a man's wife dies, I think of my own wife, and how I would feel at such a time (even though it is not a "death scene", it is all the more poignant or being a sort of mundane scene between a loving couple). Second, Kerr plays a sort of idealized version of Livesey's idea of a "the perfect woman" (and earlier in the film, he foolishly did not reveal his love to another woman played by Kerr, and so in this scene, he is losing her again). And thirdly, I am moved as Powell is moved as he watches the scene and comments on it. That, to me, is as good as film commentary on a laserdisc or DVD gets.