One thing, which in my opinion is missing, is possibility to see portal's organization structure as a whole. It is possible to display "list of Xes", "details of X" or "list of Xes associated with Y". However, it is not possible to see multi-level hierarchies or simply all entites at once. This makes it difficult to get the overall picture or to verify if everything has been configured correctly.
Because of that I created a simple portlet plugin, which adds a new portlet - Organization Chart. This portlet displays hierarchy of Communities, Organizations, User Groups, Teams and Users as a tree. This is how it looks in action:
I hope you will find this plugin useful. If you have any comments, suggestions or problems with it, let me know.