It is interesting to see the names of the people who have been involved with the symposia over time and the people who have been involved with editing the conference proceedings.
Would a thought be that there be an honour board that is created to acknowledge the contribution of long term participants/supporers of the Symposium.
Also worth considering whether there needs to be a named keynote address (eg The Pont Lecture or the Santich Address) which is a regular part of each and every symposium. Might be something where invite a key international figure to present that keynote.
Just an idea
I thought it would be useful to look at the summaries prepared by Barbara Santich on the early symposia. Like Barbara, these summaries are measured, succinct and self contained.