If, due to the nature of the War of the Ancients, you're afraid this set will place restrictions on the races playable in the set, worry not. You will be joining a faction of adventurers known as the Timewalkers, heroes who have traveled to the era of the Ancients via the Caverns of Time. Orcs and humans will be represented alongside the elves and tauren of yore.
If you're the loot-hunting type, War of the Ancients will provide with the common Eye of the Legion, uncommon Demon Hunter's Aspect, and rare Feldrake mount, which were discovered in the World of Warcraft game files as far back as patch 4.3.2.
Timewalkers: War of the Ancients releases nationwide October 2, 2012, at a retailer near you. Keep an eye on the official WoW TCG website, as they'll be starting their own previews beginning next week.