According to the wiki, there should be a pad context menu possibility in zynseq to “Import from SMF”. Not there at the moment. (I’m currently under Vangelis.)
Ok, mea culpa, the import should be in the arranger view according to the wiki and there it is.
But the subfolders are still an issue. Don’t want to copy my MIDI snippets directly in the mid folder unstructered…
The reason that the import is in the arranger is because it may create many patterns on many tracks which, although can be landed behind a single pad, is not necessarily what the user wants, e.g. importing a whole song with lots or channels may benefit being looked at in the arranger. Of course we may want a way to get a short smf into a single pattern but there be many challenges for UI.
You may wish to consider this feature request which, although different to your MIDI related folder structure, is probably sufficiently close to warrant expanding.