It will be interesting to see how the handle the event logistically. Although Epcot is a big park, there aren't a lot of popular attractions to draw guests. Innoventions is already gone. Seems like a waste to keep things like Imagination and Ellen's open for a special event since there are never any waits and there's little guest interest. And how will they handle the World Showcase? Keeping every pavilion accessible seems like overkill, yet they are a big part of Epcot's popularity.
If they allow 15,000 members into the event--and those members end up largely split between Soarin, Test Track and Norway--there will still be long lines.
The Animal Kingdom events are already sold out...just 24 hours after they opened to non resort guests.