Yes, I think everyone was surprised at the response and outpouring of support. Not so surprised about the support side since this community is, and always has been, more supportive than some others. This first event is likely to have a few hiccups and bumps along the way. The main thing is to learn from the mistakes this time and just make it better next time. It will still be a great time for fellowship with other pilots and memory making with family and friends, even if it turns into Woodstock.
Welcome to the forums, Blaine, and please don't hesitate to ask us if you need any specifics(or even generalities) on anything. We're always happy to help out if we can!
I definitely think that Flite Fest has gotten a lot bigger than they expected. Jason Uberig on KickStarter pointed out that well over 270 pilots will be attending. That is 270 KickStarter backers picked rewards that include "Pilot Registration" and that number does not include other members of the backer's family that will also be getting "Pilot Registration" for the event. I suspect that is more people having already paid for Pilot Registration than those that attended SEFF 2014 (but I do not have any information to prove that suspicion).
I bet that when Flite Test decided to hold Flite Fest, they were probably expecting 50 to 100 pilots (pure guess on my part). I doubt that they had any idea that there was so much interest for Flite Fest. As such, I suspect they are scrambling to figure out how they are going to deal with an event well over 2 times bigger than they were expecting.
Finally, remember this is their first event. They do not know what they do not know with regards to holding these events. This will be a learning experience for them. Expect mistakes and things to go wrong. They will do their best to minimize the impact of such problems and I suspect they will have a lot of help from volunteers to help make this event a success despite any problems. Things like an online pre-registration form or event a mail in pre-registration form may require resource they currently do not have as the available resource are being used elsewhere (like continuing to put out Flite Test videos and/or scaling the event to address the overwhelming success of the KickStarter campaign).
Disclaimer: The view presented here are purely speculation and not based on any official word from Flite Test.