He says, "I don’t want to dick around with fonts, spacing, indentation, etc." as if that got in the way of composition, and then recommends learning a complex programming setup and urges us to learn LaTeX?
I think I'll stick with PageFour and Google Docs, thanks.
I'm going to preface by saying, I by no means have a writing success story and pretty much made up this process as I went along, so I don't know if it's good or bad.
I never got an artist to illustrate for me, but I did what you are talking about and turned a short story (~5000 words) into a very detailed script for what I think was a 32 page comic.
I used CeltX to do it, although I had some issues. When I tried to convert it to .pdf for printing it mushed together some of the text and made it impossible to read in parts. At the time I couldn't find any remedy for this, but they may have fixed that by now. I've been converting it over to PageFour which I like way better for all my writing projects, but it's not free.
Before I typed anything up, I used a dry erase board and laid out the panels with stick figures and short descriptions of what happens in each panel.
I did my best to use exposition from the story just as guides for how the panels would be paced and drawn. Dialogue I had to chop up at times to make it more natural for speech bubbles (which I think actually helped the story anyway, because it more closely resembled how people talk).
I went very detailed on all my descriptions, because I wanted it to entirely be my story and intended to just hire an artist to create my vision. However, if you have an artist in mind that you are comfortable with or are doing it yourself, you probably don't need to be as descriptive.