If you want to avoid collections, your only option is to turn on Flatview and sort by DateTimeOriginal.
Collections still allow you to recreate folder structures, though, there are several threads on the forum.
Searching for files with DateTimeOriginal before 1900-01-01 seems to be a good approach to finding files with this field empty (it was in my testing). If it's not reliable, you could define an extra test column like this:
exifColumns.push_back(GetColumnMap('EXIF', 'DateTimeOriginal', 'DTOcheck', 'DTOcheck', 'DTOcheck', 'empty', '', ''));
and search for DTOcheck equals "empty".
Try the new version of the add-in I just posted, you should see a nice improvement in performance and stability. If you still run into problems, have a look at the logs, which btw you can simply save:
