Glad to see things moving forward so quickly.
Just remember the differences in when and how these were announced. Disney Springs has been in development for nearly 2 years after they canned Hyperion Wharf. Once development was completed with construction permits assigned, etc., then they announced it. That is why construction can begin so shortly after the annoucement.
On the other hand, Avatar was announced in September 2011 right when the partnership was first signed without much done in terms of development other than some blue sky ideas to convince James Cameron and Disney of the possibility of a theme park development on this idea being something they felt to be worthwhile. Hence, 2 years of development since its announcement would make sense before we would get any firm details on what it may include and to see signs of construction. That will take us to this D23 and thus I would suspect we should see something by then. The fact that AK has been making recent efforts to move the meet n' greets and Festival of the Lion King out of there by the end of this year would seem to suggest they are still proceeding forward with the plan for this land, no matter what is finally entails.