They needed someone that wouldn't require a needlessly convoluted excuse to be there. (Though I suspect a few scions reasons will probably border on that). Yugiri however would still be involved in Doma's restoration. It and Ala Mihgo might have been liberated, however that doesn't magically fix the nation overnight. That same reasoning would be why there should be no expectations for anyone in Ishgard or Garlemeld to appear in Dawntrail unless the story takes us back to those areas at some point.
