Not sure if I'm wasting my time asking for a LotusScript improvment but here goes...
NotesUIWorkspace PickListCollection - add an option to pass default selected documents in a NotesDocumentCollection
If using the existing method in custom applications then there are many circumstances where the user has to re-select their chosen options when editing a field. This will allow us to greatly improve end user experience.
EDIT - Hadn't noticed this similar request: