If I'm interested in a topic enough to sit through 45-60 minutes of hearing about it, I'd rather get one person who really knows their stuff delving deep than five people doing a six-minute bird's-eye view.
In ALMOST every case, the panelists didn't appear to meet beforehand, didn't check to see who was covering the same ground, and didn't work out any smooth transitions from one topic to the next. It fell to the moderator to stop whatever discussion was going on, and say "Thank you, x, now let's hear from y."
But judging by the frequency these things show up at skeptic events, I am clearly in the minority.