When using the import via csv tools, it is very easy to upload the incorrect data and make irrevocable changes to the data. It would be nice to be able to run a preview of the import so that errors or unexpected changes could be identified and stopped before they take place. There should be options to either preview or import, so those wanting to bypass the preview can still do so. But for those wanting to preview, the import should show the outcome of the imported file e.g. rows updated, deleted, created etc and then an option to confirm the import (which would then run the import for real). This would double the time taken for the import, but would catch potential issues that could cost a lot of admin time to fix.