The expansion promises a new single player campaign, new faction, new units, new spells, improved create a hero functionality, improved siege warfare, enhanced AI, and 8-12 new multiplayer maps.
Now that game's expansion, The Rise of the Witch King, presents a window in time to show the half-century battle for the kingdom of Arnor that the Witch King waged from his own private kingdom of Angmar. The Battle for Middle-earth II began this transition with a look at the other side of the War of the Ring which took place in the north between the Elves, Dwarves, Goblins and Witch-king while the battles from the books and movies raged to the south. While the hype may have slowed a bit after the movies, it's not hard for fans of the fiction to latch onto the possibility of more action set outside of The Lord of the Rings series of books and into the relatively unseen history.
The appeal of games set in Tolkein's brilliantly created universe remains alluring to a large group.