Product Updating Import
I notice when I need to import product updates I needed to import the whole file again with all the data. When you have a lot of products this is very time consuming. Because the import files need to be broke down into smaller files and imported one at a time to get the data imported.
Suggestion would be to have it so you can import just the headers needed. E.g. if you needed to import a tag you could create a file of just SKU and Tag1 in the header. When this file is imported it will add the tag for the sku.
If all the headers are needed for the import. Have a 3rd option to check. Such as Update product information if the products already exist (Does not delete any value in a field currently if exist)