It would be good to either have an external progress indication,
or tell people to open the Shortcut then run it (so you can watch
the progress in real-time). Right now the shortcut is chugging along
at about 30 conversions per minute, so converting my 1700 rtf files will take most of a hour…
Two more requests: 1) retain indents, and 2) retain vertical spacing (line breaks)
If you use NVAlt to make (say) itemized and indented lists (no bullets, just tabbed indents), that’s currently getting lost in the conversion.
And if you have lists of items separated by blank lines, a blank line is getting inserted between all items, and the original blank lines are getting lost.
There’s only so much one can do when converting RTF to Markdown, and only so many features a shortcut can offer. But if anyone wants to dig in and see if there’s a better solution, I’d love to see it.
Indents and vertical spacing can have negative effects and no effect in Markdown, respectively. Determining intent would be well beyond the scope of such a shortcut.
Understood 
Thanks for all your efforts!