Date concept insufficiency (?)

Yes fully agree with that. Also many forum discussions about new fetaures died because there was no useful way to store new data in existing GEDCOM structures. Sometimes there were workarounds using the existing structures, but the usability was terrible.

Some discussions I remember:

  • Support for DNA genealogy
  • A Heirlooms category to track all kinds of inheritable items
  • Sets as a container for multiple different objects e.g.
    • a clan = several families
    • an organisation = people and places