DAK really needs an expansion, but I still don't like the idea of Avatar. Unless the sequels bring a major increase in quality, Avatar will not have the staying power of other franchises like Star Wars and even Harry Potter. DAK already has a problem with disunity in the theming across the park, and an expansion should help solve that problem. Avatar only disjoints the overall theming even more. Africa and Asia go together, but having Dinoland and Avatar as the other main areas is just strange to me. I feel like this is Disney's way of trying to replicate the mass popularity of IOA's Harry Potter, but this plan seems shortsighted to me. They are totally different beasts.
That being said, James Cameron knows what he is doing, and it is good that Disney is keeping him on for this project. T2 was awesome and innovative when it debuted in the 90s. I'll be interested in seeing what the new nighttime show and safari looks like. It's just sad that Avatar Land won't be arriving until 2017 now. DAK really needs something new ASAP. By the time this hits, it'll pretty much be a decade since their last major attraction/expansion.