Godfather, The Best and the Worst COMMENT: 1) Who is the WORST-WRITTEN character in the novel?

Godfather, The Best and the Worst

COMMENT:

1) Who is the WORST-WRITTEN character in the novel? By that I mean, the character whose personality Puzo was not able to nail.

2) If you could get rid of one of the actors in the film and replace him/her with someone else, whom would you pick? (You don't need to name the replacement.)