I have the hardest time explaining this facet of Eberron--but as I get older, certain fantasy settings seem less relevant to me. I don't mind the presence of good and evil in fantasy--indeed, they are essential ingredients--but I like things more nuanced, with some texture to them. And Eberron had that in spades--numerous powerful secret organizations and entities, all vying for power--no assumed allies or enemies ("We're both of 'neutral good' moral alignment, right? So that means we should automatically be friends, right?").