I would pay good money to ride a mine cart through the Mines of Moria. Enter past the guardian of the lake, plunge into darkness, hear and then see the Orcs coming, flee through an arrow storm through the ruins of the Dwarf Caverns, pause on the long Bridge to be threatened by the Balrog, and then flee again out the door to Lothlorien.
This could be an exceptional dark/thrill ride hybrid. Of course the carts have no real place in the lore, but you have to ride in something. I'd love to explore Orthanc with an Ent or eat in a restaurant from Laketown. With Dueling Dragons going away, you could also do dark ride/thrill ride to rescue the Arkenstone and flee from Smaug. Sure I'd rather it hew closer to the book than the movies, but I'd take either.
I'd probably be more excited about a Tolkien based land than Star Wars or Harry Potter.