Scarlett was imbued with what could be termed "the bulldog syndrome." When she took hold of something (or someone), she did not let go. Sometimes this worked to her advantage; in one situation, it did not. Her obsession with Ashley worked against her achieving happiness. The usually realistic Scarlett viewed Ashley through the prism of Romance, unable to see him for the man he was until she had wasted much time, effort, and emotion trying to win him. Most of her obsession with Ashley, though, lay in Scarlett's personality. She wanted him because she couldn't have him.
Scarlett's determination served her well in other circumstances. After the South fell, it was Scarlett's determination that saved her family, Tara, and her own life. Above all, Scarlett was a survivor.
What was the source of her strength and absolute determination? Irish genes? A pampered, privileged childhood? When we first meet her, Scarlett is already sixteen, so the details of her childhood are sketchy. Whatever the inciting incident or combination of influences, at some point Scarlett became a person who was determined to take control of life and bend it to her will.
I too feel that silver lining shining behind Scarlett's otherwise dreadful personality. She was quite determined, and allowed herself to take quite a couple of hits from society before setting up her goals and working her head off to achieve them.
Aside from the fact that Scarlett hurt a lot of people, she still maintained her backbone and helped out Melanie during her pregnancy and during the birth of her baby, and she did work hard to preserve food for herself and for all the household when times got rough. She may have become a money hungry Jezebel afterwards when she married the third time, but at least during the times when the going got rough, she kept going.
In response to #2: The south is and always has been full of hard-working people (like Scarlett) who work with what they've got to do the things that need to be done. The north assigned the term "romantic" to the south, not the south. It may be one of the reasons for the Civil War in the first place--jealousy of a lifestyle which appeared to be one of leisure. The north did not see the amount of work that goes into growing food and other crops for the purpose of making clothing, etc. They only saw the nice weather, the uncrowded land, the rich plantation owners and their lovely daughters wandering around under parasols, and a way of life that was impossible up north due to crowding, dirty factories, and harsh winter weather. This explains the number of snowbirds who still plague the south during winter months and the retirees from the north who settle permanently in places like Miami.
The Romance of the south is the unspoken words in places like Charleston, NC and Atlanta, GA that only southerners understand. How to act, how to treat others, when to wear gloves and hats and when not to. In a word, it's manners. Scarlett understood these manners, but she also recognized that desperate times called for desperate measures. For example, before and after the war of northern aggression, no southern woman would ever make her gown out of drapes. However, you work with what you've got at the moment. Rules change. Scarlett is a perfect representation of survival with gentile attitude. Something I fear will never be completely understood by those born and reared outside of the south.
Scarlett O'Hara is an icon for a reason; she personifies the Southern woman, who will do whatever it takes to survive and thrive, and still look beautiful doing it. Scarlett is a force of nature; whatever life hands to her, she seizes it and gains the upper hand. She is the original unsinkable Molly Brown.
Scarlett's strength in the antebellum Old South is her ability to charm men into seeing only her beauty, while her intelligence stays hidden to them. This ability set apart powerful women for centuries and reached its zenith with the rise of the Southern Belle. Women were able to gain power and influence only indirectly, as a result of their relationships with men. Beauty was a prized commodity and those who possessed it were (are?) able to parlay it into wealth and power via marriage. Even brides with handsome dowries were not as desirable as those with beauty.
Once war ravaged her home, Scarlett's inner strength and intelligence superseded her beauty and charm in saving her. She became a successful businesswoman. The Steel Magnolia emerged from the helpless Southern Belle.
Perhaps what is what the South lacked as it went to war with the North. maybe she represents what people should have been like as opposed to being Romantic. In "Huck Finn," the Romantic ideals of Tom are definitely illusionary compared to the Pragmatic and Practical Huck. I can see the great disparity between a false sense of Romantic glory and Realistic Pragmatism in Gone With the Wind.