I'm reminded of, say, playing softball with someone who used to be a star high school baseball player, maybe with some minor league pro or semi-pro experience before washing out. And while everyone else is playing at the level of middle-aged hobby softball, sometimes striking out, grounding out, or making an error or two, that person is hitting every ball on screws, fielding everything hit near him, and making crisp, accurate throws.
Or, when a professional cook or chef makes dinner for friends. Or when you see a professional musician noodling around, and while you need sheet music to play, they are just banging out requests by ear. Basically, Rodney's a pro. This is what he does to eat. He's got habits developed from having to do this kind of thing at work, and he just naturally does them in his home game, too. He's got shortcuts to write things out faster, and his neural pathways are primed far more than most for the spilling out of game material.
All of which is to say, I don't think Rodney's advice, nor his example sheet here, are unsuitable for beginning DMs. I think we're just seeing the effect that doing this for a living has on one's home game.
