At the Boston Sakai conference, Josh Baron challenged the community to do some pie-in-the-sky (PITS) thinking about what would be fabulous activities teachears and students might do in the future using Sakai. Stephen Marquard recommended the community create the most complex scenarios (MCS) to drive Sakai 3 development. The teaching and learning community in Sakai should answer the call and document a collection of powerful ideas and challenging dreams.
The portfolio group has been thoughtfully considering this for the last few months on our weekly calls. We have a pretty significant list here: http://confluence.sakaiproject.org/display/UX/Portfolio-related+vignettes