Why is "Rumpelstiltskin" said to have near perfect "structure" in fairy tales?
Fairy Tales are cultural tales told to reflect certain cultural traditions and moral truths. There are certain plot elements that always occur within fairy tales. Some of these elements are a character being banished, or confronted with a problem, or being forced to accomplish some difficult task (like spin straw into gold). There is always also a miracle.
The link provided is the text from:
Jack Zipes “Cross-Cultural Connections and the Contamination of the Classical Fairy Tale” in The Great Fairy Tale Tradition: From Straparola and Basile to the Brothers Grimm, ed. Jack Zipes, New York: WW Norton & Co., 2001, pp. 845-868.