Well I think the new land will be a big enough deal that it will draw lots of crowds when it opens regardless. The public is starving for new attractions/experiences at their resort.
Now Disney can look forward to 4 additional years of free press/marketing after the park opens.
I just wonder what will happen If Avatar 2, or 3, or 4 flops....do you still keep going?
How many stories could he possibly be dreaming up? My guess is that the Earth will eventually become inhabitable, and the story of Avatar will involve the great migration from Earth to Pandora and all the terrible things that happen in between.