AoS insectoids were only mentioned on a Underworlds season meanwhile Chaos Duardin were mentioned during the new Lore at the start of the edition with the Kruleboyz. The difference is noticiable, with the insectoids being an isolated faction and the other being part of the events and a real active faction.
Being objective, Chaos Duardin were more active or named on battletomes this edition than Malerion or Ushoran.