Some folks mentioned the whole "combining panels on same topics" and I am completely against that given my previous experience. I'm one of the guys running a panel on Takashi Miike this year. Mine is called "Violence, Sex, and Death" while the other is called "The Hired Gun of Japanese Cinema." In 2009 I ran the same panel and another group was covering the same topic so we were forced to combine into one. I'm someone who has seen the vast majority of Miike's 70+ films. How many had the other group seen? Two films. TWO. And you better believe when it came to panel time they had barely anything to say no matter how times I passed them the mic. They got free badges while my co-panelist and I did all the work.
This year I got in contact with the other group running a Miike panel to try and figure out a way to make things different but ultimately we're each just going to stick to our original plans. It helps that they're each on a different day so hopefully different audiences will make it out. If I could I would gladly go to the other Miike panel, but I'm running another panel during the same time as that one. I wish that group the best of luck.
I can for sure speak to your point on the combined Panels. It was an idea we had in that year due to limited function space issues as you I am sure you were aware. We found some that did combined went extremely well and others just did not get along or had entirely different topics. We tried to "Mediate" so to speak between each panelist and having one combine the other, but some just would not have it. We stopped the idea entirely the year after and we just decided to review panels a bit more closely. This year with so many function space we can let a few of the same topics go and then consider all options for next year as we will have excellent feedback/data on every panel this year.