I like the shorter format. It's always easier to find 15 or 20 spare moments than it is to find a free hour to watch a video. Though I do imagine it's difficult to decide what to cut and what to keep, a problem every editor has to face...
You'll likely want to watch one of the other videos on Ross, where we actually discuss his conception of prima facie duties (notice the plural). It would be good to read chapter 2 of the Right and the Good as well -- available online if you google it -- then you'll have a better basis
Good stuff, it seems Ross has some very good ideas. This lecture reminded me of my time in the a UK school, when I was young. 30 kids in a drafty trailer, recovering old textbooks, so they couldn't fall apart. It's improved since then, at least resource wise.