Currently the field VariantOf is required when importing an excel file in PIM, but the field is actually only required when baseproducts and variants are created, not for updates.
Making the field non-mandatory and instead adding a validation when the field is missing on create only would make import more useful.
It is for example common that other applications do not have Litiums concept of baseproducts, so the id required for VariantOf is missing making it impossible to directly import a file exported from that application, even if the application has the unique article number.
Additionally it would be nice to have an option in the import to only update values, e.g. a checkbox "Update Only"