Panels are a great way to look at a subject from several viewpoints. Unfortunately, they can also become slow, boring torture when panelists and moderators adopt the "speak-only-when-spoken-to-or-questioned" attitude.
While there are many reasons why most people don't get their best ideas at work, there are at least as many why organizations don't get their best ideas a work -- the main one being their tendency to rely on what I like to refer to as the "creative elite."
Even more deadly is the 'report back' session. Possibly you had a good discussion in your syndicate; you enjoyed it and found it a worthwhile use of 45 minutes. Now you have five minutes to convey this to the group as a whole. Why?
There is often a certain level of discomfort which increases productivity, but if you go beyond it productivity falls off abruptly. So the skilful leader takes risks with discomfort, but keeps the door open so he can take the temperature back down again.