I'd like to suggest offering a faster way to select multiple specification attributes per item. Perhaps a checkbox system. Select the attribute, then the options available are listed as checkboxes. Select the items you want and possibly have the 'Allow filtering' and 'Show on product page' as an option for each attribute option or select it once at the top for all boxes checked.
Our use case for instance, we have an auto parts website that requires Year, Make, and Model spec attributes to be selected. Typically, we have 1 Make and 1 Model per item, however, we may have 16 different years to select. In another instance, we may have several makes and models as well.
In some situations, I can export products and modify them to include all the necessary spec attributes, then re-import them, but still takes quite a bit of time.