The bold part is the reason dealers are charging so much. WW, from what I've gathered, is an expensive con to set up at regardless of location.
$1,100 per booth here in Cleveland. If you price your books at 10% over what you could get on E-Bay then (even factoring E-Bay fees) you would need to sell $6,000 in books before you are getting what you can get on E-Bay and that's assuming you have no other expenses. Its not physically easy to sell at Cons compared to online sales so I can see why people mark their books up 20% over E-Bay but then you have people start walking away with prices that high. Tough market to succeed in.
I think this happened at Heroes in 2012 or 2013. Could've been the fact that Stan Lee was there, but prices were aggressive. I heard dealers complain. I couldn't understand it. They were pricing themselves out of business.
I view WW as more of a 'pop culture' con anyway. As a dealer, I would bring diverse group of product - probably more pop culture items than comics. That's me speaking as an attendee though. Point is, I think you've got to know your market and clientele base before setting up.