One of the best scenes in the entire series. I always looked at it as Mike reflecting back on his family and how he has lost them through his selfish actions.
Although Mike always said that it was all business, there was always a personal theme underneath all his moves.
IMO - it is the perfect transition into Part 3 where Mike is filled with guilt.
And with Brando not being in the scene - it adds to his character, his aura. By then, the character has almost become a myth. And with seeing De Niro play the part so well eariler in the film, to see Brando then wouldn't have been right.
I always was happy this is how it turned out.
And if Brando was too stubborn to do a day's worth of shooting for a director who cast him in the role of a lifetime, then he didn't deserve to be in it.