I must say, when it comes to personality, Sarabi is, for me, the most powerfull character in the movie. She moves with grace, she acts like a queen, but is a loving wife and mother at the same time. She´s a charismatic leading lioness of the hunting pack, and after losing both her husband and her son, she refuses to let her head hang down. She goes on and puts her Pride above herself. Pride is the first word I think of, when I see Sarabi. In my opinion, she sure deserved a larger role in the movie.
Nala was a loving wife as well for Simba, but she does not have the wisdom Sarabi has in the first movie. Maybe thats due to life experience and age, but Sarabi is, for me, the most ’queenly’ lioness of all lionesses that appeared in the movies.