When for example a batch rename sequence number of 1 digit is selected, if there are more than 10 photos, it repeats the sequence numbering 1-10 (or 0-9 or 1-9, whatever it is). I suggest that rather than doing this, it should simply move on to the next number. So if there were 20 photos, the sequence numbers would be 1-20. If you told it 2 digits, they would be 01-20. I.e. the number of digits specified is a LOWER LIMIT, but the actual number of digits used ought to be as many as necessary to provide a unique sequence number to each renamed file.

Currently under Batch Rename there's an option to "Preserve current filename in XMP metadata" but there's no way to get rid of these preserved filenames after they are no longer useful (or simply because they disclose outdated or confidential information).

One way to do this would be to add a "remove preserved filename" checkbox to the Batch Rename dialog box; that way you could just rename the the files a second time to clear the preserved filename.

Another way to do it would be in the metadata panel; just make the "Preserved Filename" field deletable. You could also add a command to "Remove preserved filenames" to the Metadata panel menu and Tools menu.