I think Disney missed a huge opportunity with replacing It's Tough to be a Bug. The Tree of Life is the thematic heart of Disney's Animal Kingdom. When you arrive through the gates, you begin a journey from the developed world to nature. This process begins through the Oasis section. That land represents your expedition to find the Tree of Life. After journeying the vista opens up and the thing you've been searching for- the Tree of Life- appears triumphantly.
The Tree of Life is the key to the whole park. As the physical embodiment of nature, all the areas of the park tie back to it. The Tree of Life essentially opens "portals" to discover nature. In Africa we see how individuals coexist with nature to bring economic development and prosperity to everyone. In Asia we see the dangers of attempting to exploit nature. In Dinoland we see how nature becomes part of the stories we tell. Avatar (I don't like its placement) tells the story of working to restore nature.
Animal Kingdom would have been fascinating if it had been allowed to be built out as intended. There's reason to believe that each of the seven continents would have gotten a land eventually. We knew of four- Africa, Asia, Dinoland as NA, and Beastly Kingdom as Europe. That left South America, Australia, and Antarctica.
At the center of the Animal Kingdom was the place where you began your adventure. The Tree of Life on Discovery Island.
As others have mentioned, originally a Lion King show was supposed to have been in the Tree of Life Theater. This would have discussed the Circle of Life. Even that represented a compromise. What if the Tree of Life Theater featured a film that really told Animal Kingdom's story? Similar to how Spaceship Earth holds the defining ride of Epcot.
Disney now owns National Geographic. If they need a synergy tie in, why not have National Geographic participate on making a masterful nature film worthy of the park? And if they're concerned about it not appealing to kids, they could alternate the film (similar to the French the pavilion) with something more IP centric.
The infrastructure exists to tell the story of Disney's Animal Kingdom. Zootopia doesn't cut it!