> What are the major innovations in Dungeon World compared to D&D 3.5/Pf/4e? Why is Dungeon World (or Apocalypse World) considered a seminal work for innovative mechanic design?
A good answer would contain a short discussion of each of the major innovations of DW over older D&D variants, and what problem this change solves. This also applies if the mechanic itself is not new but is used in a novel way.