When artifacts and semi-artifacts are expanded upon in the near future they should be redone in such a way that they can potentially hold souls in the same way creatures do. This allows for things like artifacts that regenerate their wearer after death, intelligent and perhaps malicious magical items, and artifacts that draw their power from imprisoned demons, djinn, ghosts, gods, etc. This actual application wouldn't necessarily need to be added now, but just making it something that artifacts can do opens a lot of lore possibilities for them and acts as framework for massive expansion.
Ideally this should be expanded to whatever non-artifact items seem reasonable and to body parts whenever those items get redone. I'd love to see a necromancy curse that requires a small dismemberment to activate and keeps the creature's soul in the finger, toe, whatever, so they can't be destroyed until someone uncovers a book describing that body part's location and then burns it. This would allow some magical villains to be persistent threats throughout a world's history, regenerating periodically until some sacred item is smashed. At the same time it opens up the possibility of trapping some terrible villain in an object (which should realistically then be an artifact) and dropping it into the ocean or wearing it to channel their power.