In a folklore class I took in college, my instructor told me something that I have never been able to forget. He stated that a healthy story is one that is retold not only many times, but in many variations. It is only when a tale becomes static and conforms to one storyline alone that it runs into the danger of being lost.
Would Atlantis or Camelot still hold the same mystique if their rise and falls hadn't been captured in ink by so many pens? Would Cinderella be half as glamorous if she hadn't lost so many slippers at different balls? I wonder.
I believe the allure of the story retelling or spin off is that it starts with a place/premise beloved to readers, but then takes them on a brand new journey. The Child-like Empress knew this when she entrusted Bastian with her kingdom's last grain of sand so that he could rediscover and "rescape" Fantasia with the power of his own imagination. *(Read Michael Ende's The Neverending Story)
Story variations not only allow, they encourage the expansion of horizons that people sometimes forget still have worlds of room to grow.
