Just a random idea.
Tarzan's Treehouse is a cool place but is definitely beginning to show it's age, especially since the whole Tarzan-fad died down. So whynot replace the treehouse with the museum-like airship of Charles Muntz, the adventurer and villain from Up. To theme it appropriately to the land's time period (1930's judging by Jungle Cruise and Indiana Jones Adventure), the airship would be inhabited by a much younger Muntz, still in his "youth" (However old he is when Carl watches him in the movie theater as a kid). Inside the scaled-down airship (Crashed in the tree), guests walk past various artifacts from around the world (Such as the skeletons of imaginary jungle beasts), ancient statues, pirate treasure, etc. Some of these elements are interactive, providing a rather entertaining walkthrough. A map in Muntz's barely-seen bedroom (Guests look in through a porthole) shows that Muntz was headed towards the Lost River Delta in India, searching for the so-called "Temple of the Forbidden Eye." This kind of ties in the walkthrough to nearby Indiana Jones Adventure. He almost made it to the temple, but crashed a bit too early. Some of his talking dogs can appear while Muntz himself never would appear (I can't imagine him in costumed character form, lol) nor would Carl, Russell, or Doug (This takes place before their time, even if Carl was a kid).
Unless Disney remakes Swiss Family Robinson, I highly doubt the Swiss Family Treehouse will come back, which is why I have come up with another idea which isn't themed or based upon any movie:
Professor Marvel's Treehouse of Oddities. Professor Rolly C. Marvel has nothing to do with a certain comic book company; he is nothing more than an eccentric inventor with a hunger for all things weird. He's so weird in fact that he has built a half-organic half-mechanical treehouse in a giant jungle tree, making it a museum to showcase all his weird belongings from around the world. This would basically be an Adventureland reincarnation of Rolly Crump's unused Museum of the Weird concept. Some of the museum's exhibits include a conservatory for man-eating plants, the fossils of bizarre creatures (Similar to those in Muntz's airship), unusual contraptions and gadgets, and the "Hall of Sight," a corridor featuring various statues and paintings representing human vision. Two of the statues have had their eyes blocked however, a statue (Now just a head) of Mara and a statue of Medusa. Both have had their eyes covered by tape to keep unlucky guests from being sent to the Gates of Doom or turned into a stone statue themself. The main exhibit however would be Marvel's pride and joy - the last remaining dinosaur...which is actually his dog dressed up like a dinosaur...obviously this walkthrough would feature a lot of interactivity.
Which one of the two ideas presented would you prefer? Muntz's airship or Marvel's treehouse?