Loose talk backed by some evidence implies that the next expansion for Lord of the Rings Online is going to be Riders of Rohan. Not only has Turbine taken the trouble to reserve the web address, but it fits with what is, to me, a logical progression within the outline of the novel.
See, The Lord of the Rings is actually not a trilogy. It’s really one big novel divided into six books, split up by the original publisher, and each traditional volume sold in bookstores contains two of these. The content that launched with LotRO more or less corresponded to the story in Tolkien’s first book; Hobbiton and the Shire and the journey from there to Rivendell, covering places like Weathertop and the Barrow-Downs. The first expansion was called Mines of Moria and covers the material in Book Two: the trip to Khazad-dum and the escape to Lorien, and probably Dunland.
It therefore makes perfect sense that the second expansion is going to cover the contents of the first half of The Two Towers, Rohan, Helm’s Deep and Isengard, and introduce Saruman as a major player. It’s also possible that we’ll see a new human starting area, I should think. Furthermore, extrapolating this into the future and assuming that Turbine sticks to this development plan, we can expect that the third expansion will introduce such areas as Ithilien, Emyn Muil, the Dead Marshes, Cirith Ungol and probably Dagorlad. Logically, then, expansion four primarily deals with Gondor, probably in several zones including Osgiliath and Minas Tirith, and possibly Southern Gondor as well, along with such places as the Dwimmerberg. This leaves Mordor and surrounding regions, probably including the Black Gate and Minas Morgul, to the fifth expansion.
After that, who knows? And Turbine might not stick with this straightforward plan – there’s certainly all kinds of other stuff going on during the War of the Ring, including an assault on Lorien and a major conflict between Orcs and Easterlings and the Men of Dale and the Dwarves of the Lonely Mountain.