Quote from Blizzard staff
Inscription
* Inscribers will create glyphs that allow players to modify their spells and abilities. (Eurogamer.net)
* Going by the first recipe, which requires Peacebloom, they'll rely on the herbalist gathering profession. (Eurogamer.net)
* Every player will get a new spell book page to which they can add six glyphs - currently, four major and two minor. (Eurogamer.net)
* Major glyphs will be effective in combat - adding damage over time or stun to a physical attack, for example - while minor glyphs will give convenient or cosmetic improvements, removing the need for some spell reagents. (Eurogamer.net)
* Glyphs can be sold at the Auction House (Eurogamer.net)
Enchanting
* Allowing enchanters sell their enchantments at the Auction House is still planned.(Eurogamer.net)
Lake Wintergrasp / Vehicles
* The new vehicle technology, which introduces physics and handling characteristics - including inertia, turning circle, grip and suspension bounce - to land and airborne vehicles and special mounts. (Eurogamer.net)
* It also allows for up to eight passengers per vehicle, and brings up bespoke action bars and skills for vehicle and turret operators. (Eurogamer.net)
* It was intended to be used solely for PVP siege weapons - Dwarven steam tanks, Forsaken plague spreaders and Orc demolishers. (Eurogamer.net)
World
* Even if you'll be able to meet him as soon as you reach Dragonblight (LVL 71-75), the final encounter against Arthas won't be until the last patch of the Lich King cycle. The Icecrown Citadel, will appear after launch. (Eurogamer.net)
* Dragonblight will also let you reunite (violently) with the Scarlet Crusade. (Eurogamer.net)
* Players will meet a lot of monsters from Classic WoW in the Grizzly Hills, including Furbolgs, Kobolds, the Venture Company, and Worgen Werewolves. (Eurogamer.net)
* Arugal has been resurrected and now leads the Worgen Werewolves in Grizzly Hills. (Eurogamer.net)
* In Grizzly Hills, you will also find an evil sister city to the Alliance capital, Ironforge. (Screenshot ?) (Eurogamer.net)
* The Argent Dawn faction returns in Zul'Drak. (Eurogamer.net)
* In Sholazar Basin, you'll take part in a faction-reputation war between the Wolvar (sentient wolves) and Oracles ("the next evolution of the Murlocs" - a worrying thought). A much lighter take on reputation gaming is promised here, with players actively encouraged to defect to the other side at will. (Eurogamer.net)
* The expansion will contain a lot of "vehicle quests" as an evolution of BC's bombing runs - throwing flaming oil at Worgen from horseback, airlifting supplies in a gyrocoptor, and yes, mammoth wrangling. (Eurogamer.net)