Would you like to add OAuth support or other auth mechanisms like CAS? =) I didn't find documentation for the "WAGTAIL_PASSWORD_MANAGEMENT_ENABLED" option.
We already support LDAP auth, and CAS and / or Shibboleth is on the roadmap for the near future. More importantly, we'll have proper Sphinx docs soon, with details of the features that are already available.
Yes, please keep that focus. A well-focused project is both refreshing and produces extraordinary results. You also appear to have a 'bigger-picture' view than many CMS creators - i.e. on the designers and the people who end up using it, not just the developers.
Congratulations Tom!