With elementary's focus on UX design, I'm wondering
- How elementary does usability testing;
- How often elementary does usability testing;
- How the results are applied to making changes to the design and flow of the applications and shell.
By usability tests, I mean sitting down with normal folk (not people you know or people who use elementary or other Linux distributions, but also people who would be good representatives of your customers) and watching them try to use your applications and shell to accomplish tasks.
As you already know, this kind of research is crucial to UX to avoid subjective bias. In my time as a UX architect I've learned that design is just as much science as it is an art.