While I agree with the author's intent, many of his proposed solutions are in conflict with the basic nature of open source development which largely rejects the notion of up-front design. Most sucessful projects rely on "evolution, not intelligent design."
I do however agree with the author's suggestion of design awards. I think they would have the potential to establish the idea in the community that design (both visual and ergonomic) is just as important as coding prowess. All open source developers want to create popular applications and they want technical recognition for their work. Just as developers recognise the importance of good coding craftsmanship, so too usability needs to become an important technical consideration in evaluating technical quality.
Another approach would be "design makeovers." Within both the GNOME and KDE communities, exist many small projects written by newer developers. A sponsoring organization, for example a Linux magazine, could select a small project and give it a "makeover." This would involve a couple of experienced coders and a designer who would apply (with the cooperation of the original author) a set of fixes to the UI. The final result would then be presented to the public (along with a lot of before and after screen shots) with a detailed explaination of the improvements and their rationale.
While usability and visual design may require talents that do not come naturally to all developers, we have seen (in the case of stronger security design, for example) that the development community is not incapabable of adapting to new standards of technical excellence. All it takes is for the community to be sufficiently concerned about the issue.