Primarily, my interest (and request for enhancement) would be any solution which would allow for easy recovery from a Windows crash 
. Ideally, that would involve automatic save/backup to a temporary file for each open text file (particularly including those not yet named/previously saved). Such temporary backup files would then be cleaned up upon a formal save (via the Save-As dialog) or a negative response to the close dialog (Save Changes? Yes/No). Elegantly, TextPad would then be able to recognize upon opening that a crash had occurred (presumably from discovering existing temporary backup files) and offer to restore to the previous open state. Of course, if keeping a list of the currently open files is too much, it would be almost as good if it merely offered to restore/open a selection of some or all of the temporary files it finds that hadn't been formally named/saved. Indeed, with that latter approach, once a file is formally named then the current automatic timed save would be sufficient protection (no temporary file required).
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Further Remarks
Some editors have offered much more elaborate solutions, including keeping multiple backup versions (allowing you to restore to various previous instances of each file), as well as maintaining an undo list of the changes between the various saved versions. Another automatic save option involved providing a choice of several automatic file naming schemes to allow for automatic save. I'm not suggesting these, merely mentioning some other possible approaches.
However, the existing timed automatic save might be satisfactory with the addition of an automatic naming scheme and a convenient mechanism by which to quickly select and reopen files that were automatically saved that way (which would mean that the existing automatic save could continue to be used the way it already does for "named" files, the exception being just those not formally named/saved).