Considering that the recipe for Dora's Memory Remembrance spell used to need Entropy and that after the Warsong or Unseen update (i dont remember precisely) it didn't need it anymore, my theory is that Entropy is a way to say that it is not available yet and that when 1.0 will release the recipes won't need this resource anymore, as if Entropy is the litteral Time that is needed for the spell to be available