I seem to remember an interview with Olivia De Haviland, who was definitely the "good " girl in Gone With the Wind. She thought it was harder to play a good girl - I guess she thought it was harder to stay in character.
I found Melanie and Ashley, tiresome characters. Melanie was stronger than she appeared and Ashley was weak. I couldn't understand why Scarlett wanted Ashley instead of Rhett. I mean...COME ON! That scene when Rhet picks her up and rushes up that long curved staircase, is epic.
Did you know that Olivia is 98? I always thought that her name and Joan Fontaine's name were made up Hollywood names. However, de Havilland is the real name of their father, and Joan changed her name from de Havilland to their mother's maiden name, Fontaine. Who knew?