We just started the planning phase for TSSJS in Vegas next March (2007). It is really an interesting process that takes a lot of effort from a number of people. The biggest challenge is to keep the symposium fresh by finding new speaker with interesting things to say and can say it.
Another interesting challenge is balancing the needs of vendors, speakers, and attendees. I think that many developers are interested in seeing what vendors are up to, I know they are not interested in pure marketing pitches. We are kicking around an idea that I think could make everyone happy.
We are also looking at adding more case studies and to further deformalize the BOF sessions. BOFs should not have many if any slides at all IMHO. Dr. Heinz Kabutz and I did a BOF at last years TSSJS in which we didn't use a single slide and I think it was very well received. We were very interactive and we drew from people's experiences in the audience.
What we confirmed is that it isn't only the speakers that have interesting things to say.