So... a question/thought about other Disney parks and Avatar. If the expansion is well regarded and especially if the rides are very popular, we could easily see them cloned in some capacity to other parks worldwide. I'm skeptical that we would see an entire land anywhere else due to the space limitations at other locations and also because it becomes a more problematic theming in other parks.
It's long been rumored that Paris will get something Avatar in the Studios park in the future. Seems quite possible that the Soarin'-ish ride would end up there especially since Soarin' itself is not in the resort. Although we have seen rumors of an expanded Star Wars for their castle park, I haven't seen any plans for any additions for the Studios there except for Avatar.
Now, I wonder about DLR.... One of the strong things we have heard is that Toontown will be replaced with a Star Wars themed area. If that happens, would Star Tours move from its present location in TL to the new area? Seems likely rather than have SW attractions in completely separate areas of the park. But if that happens, what would become of the Star Tours plot? Could it become a copy of the Iron Man Experience going into Hong Kong? Maybe, but it also could potentially house a Avatar attraction -- Disney has in recent years used TL as a sort of "sci fi fantasyland" and Pandora fits into that motif (arguably better than Iron Man or any other Marvel stuff), plus they might be using Marvel in DCA in the near future.
My point being that is probably makes sense to not think of Avatar as just an investment in DAK since we might be seeing some aspects copied worldwide, spreading around those development costs.