Interesting reading. The Amazon series is covering the second age. Minas Tirith wouldn't be a possible set since it wasn't constructed until the Third Age (if you follow the Tolkien canon). Gondor did exist though in the middle of the Second Age. Sauron, as well. You'd probably see some Numenorean based sets, maybe a Balrog or a dragon. I would bank on LEGO releasing a new series of Tolkien based sets. They were popular (the Hobbit and LOTR sets. The fans of the sets typically are fans of the books and films. LEGO wouldn't miss the opportunity to sell to a market base that is at least as large as the Star Wars fan base.