This directory is empty, remove dir? (can be undone, by creating the dir again)
This directory is NOT EMPTY, remove dir & all its contents? (cannot be undone!)
This directory has <size> of data in it, remove dir & all its contents? (cannot be undone!)
...<size>, for example, would say "100MB" or "100 bytes". There should be the option of disabling each confirmation separately, like allow removing an empty dir without confirmation (rmdir <dir>), but still confirm on deleting a non-empty dir (rm -r <dir>).