It seems like the annual Less Wrong survey is already doing a good job asking simple, easily classified/quantified questions like "where are you from". So the comparative advantage of these interviews might be asking longform questions like "what's the most valuable thing you found in a meetup", "what's the thing you are most surprised does not appear on Less Wrong", etc.

Other half-baked question ideas:

• Do you have a note-taking system? How does it work? What software do you find really useful in general? (Google Chrome extensions, webapps, phone apps, etc.) (If anyone is curious, I described my note-taking system here. It's a nice low-pressure way to keep track of ideas for Less Wrong posts that I will probably get around to writing at some point.)

• How has rationality informed the things you do in your career? What rationality lessons have you learned in the course of your career?

• What rationality techniques do you find most useful? Have you discovered/learned of any that Less Wrong doesn't discuss?

James Miller comes to mind as a person to request an interview of; he's an tenured economics professor.