I know you're just font as an example, but doesn't your markdown editor also shove a font in your face? You can adjust default behavior in Word just as well as in another editor.

Anyway, to work within your analogy, I would say that Word lets the write do a bit of a 'mockup' of the set with nearly 0 effort. Like "I want a table here", so 2-3 clicks and you have it. Then you can "let the director" take your mock up and flesh it out properly later. As a writing, it helps me to see the mock up of the product as a go, but I want that mock up to be effortless. And as I said above, I do some work up front to make sure that Word's mock up looks good (or good enough).