I will just add that I agree [content] Quality is a strategic goal we have made little systematic progress on (much progress was made in sheer coverage, of course, e.g. via funding and support for content-centered initiatives such as writing and photo competitions).
In the Grantmaking department, we are definitely interested in ideas and proposals to improve (and measure) quality of content on the projects, and not just of outside assessors, but also internal approaches to assessing quality (serving different purposes, to be sure).
I encourage those with concrete ideas to propose something, perhaps in the IdeaLab[1], for further development and refinement.
Asaf
[1] https://meta.wikimedia.org/wiki/Grants:IdeaLab