+1 on @jonm’s suggestion, assuming there isn’t a usefulness of having UUIDs for things like PSets?
For instance, let’s say in an ideal future we can reference one IFC file from another. The architect models a room. He references a IFC files from a sustainability consultant. The sustainability consultant is only responsible for adding relationships and psets, and so therefore ideally his IFC file only contains those relationship and pset definitions. Or maybe the QS has an IFC file that only contains QTO elements. Is there a disadvantage to removing the UUID here? What is the UUID is the only way the QS has to link it to costing items? What if the UUID is way a sustainability consultant references data in his models? What makes an element “non-permanent”?