My theory on this was the concept art was to get people interested in Saturday's events, knowing that there would be no reveal of anything on the 20th as we thought. Anyone willing to pay the price to go to this event would be just happy to be in the company of Joe Rhode, James Cameron and any schlep they threw out there. Still, you would've thought if you're gonna fly Cameron out for an event like this, you'd bring a little more substance to the table.
But i'll give it to Disney's marketing in this sense where I think
@Mad Dog over-looks it when you said "where is the great marking machine?" or whatever. They created basically a weekend full of hype around a land that they still have yet to reveal much about at all. Meaning that with this weekend out of the way, i'm expecting a FLE type reveal where every 2 weeks or so starting in about January or February they'll reveal more and more. By not revealing much now, it left them a crap ton to release leading up to the opening of the land next year.