It would be helpful to be able to customize the form to include a notes box so that constituents can add additional information that would be helpful to an organization, in addition the ability to add additional constituent info like the title and aliases fields. This could also benefit other organizations. Also, the join message is generic. It would be helpful to be able to customize that message to our constituents so that we do not have to send a separate email to elaborate further.
For it to truly be a PORTAL, there should be strong consideration given to these suggestions. Employment history is another set of fields that users should have the ability to update themselves, or at least the addition of a "narrative" field where constituents could indicate life events such as marriages, children, new jobs, etc.