"substantial writing"...? really? "serious" writers?
I could list 10,000 pieces of GLORIOUS work that was crafted on nothing more than "pen" and "paper" ... or perhaps just "paper" and "ink" and "typewriter"...
PEN + PAPER == Maximally-minimal "app"...
and in that way, with Desk, I was attempting to create an homage, of sorts, to the "old way" of creating great writing work.
keeping it simple, effective, useful.
minimalist apps are for the serious and the playful, for those that are writing epic novels (one user of Desk is a multi-New York Times winning author) and those that are, as you say, "pretending" to write (like my 8-year old daughter, perhaps: http://john.do/gift-writing/).
but, it all, at the end of the day, is still writing...
"There is nothing to writing. All you do is sit down at a typewriter and bleed." ~~~ Ernest Hemingway