Did you actually see that scene? Is it in the UK DVD set? I thought it was never released.
Of those I've seen, the long one with Michael and the Don about to leave Connie's wedding, and then visiting Genco on his deathbed, is the best. It provides valuable perspective on Michael's statement to Kay earlier at the wedding, "That's my family, Kay--it's not me"; and on Michael's telling Kay that Tom is "a good lawyer; I think he's gonna be consigliere." Plus Brando provides two superlative performances: one where he rolls his eyes when he askes Michael if "your American girlfriend" got home ok; the other when he tells Genco he has "no such powers" to save him. Bravo!