This page is great.
Some information gets smarter with more input, and some gets less smart with more input. One of the hard parts about SEO is that everything is debatable. Some additional opinions will poison data, whereas others will make it way better.
Even beyond the debatable is that questioning the right people makes some data seem much more credible and so much easier to spread. If you seek input from the right people in your industry, like Danny Sullivan in search, you can help ensure that an idea spreads far and quick.
I bet that within a month or two that page will be the most well linked document on the SEO Moz site, and it is something just about anyone can do in any industry. Design problems, site usability problems, gardening problems, airplane landing problems, etc etc etc.
The key is to know who to ask for help and to be trusted enough to where they want to help you. Of course you also have to appeal to their ego to where they want to help you. Other than including MM in the data sources I don't think there is much Rand could have done better to make that page more linkable. I love the smiley faces.
Another nice thing about the page is it could be resorted, asking the same questions to self proclaimed search spam gurus. Give DaveN, Greg Bosers, Oilman, Baked Jake, and a few other guys the same set of criteria and see how they answer it. Then those feedbacks can be cross compared.
A Google Zeitgeist of SEO factors that has biggest gainers, biggest losers, and top ten would be amazing link bait that reminded people to visit frequently and link in every month. And then maybe redue the whole ranking factors thing once a year or so.
Good idea Rand.