I do have a couple practical questions though:
You're thinking a checkbox over somewhere near the left-hand side that says something like "include auxiliary files from the source directory" or would it be a particular mode? I just wonder though because all the stuff below the modes is about the destination directories, not the sources. But whatever, I guess.
Would these files preserve existing file names for these unimported files, or would it use the Filename rule provided? Or maybe some kind of automatic naming scheme (that seems bad to me)?
What about collisions? Should they stay behind? Pop up a warning? Move anyway and append numbers?
I also definitely think they should show in the preview box, which I assume would be part of it.
- I'd put it left aligned at the bottom of the Preview pane.
- The Preview window could show non-imported files in a distinguishing font face (italics maybe), or color, or identifying icon.
- The option could apply to all of the modes: Rename, Copy and Copy and update database... It would be greyed-out when mode Update database to point to new location ... was selected.
- I suppose the Filename rule might be useful, but probably not typically, for non-imported files. Cover art has strict names, or probably sufficient names already. So I'd vote that for non-imported files, the Filename rule when enabled is ignored. Only the directory rules are used.
- Collisions should probably be handled as they are today, with appended numbers. Users can then sort out their collisions / duplicates at another time.
- Currently when MC errors while moving some files in a directory, the files and metadata can become a mess and detached, so nothing this mode will do makes this worse. Hopefully someday MC will fully error-correct partial moves and make directory moves act and feel more atomic.