Wowinsider has a very hot blog covering the Lore and Quest panels.  Turalyon and Alleria are missing and we might find them in a future expansion.  They probably entered one of the seven portals created by Ner’zhul.  New Heroes will join Northrend with Tirion Fordring and his new Order of the Silver Hand.  Chris Metzen said Tirion and the Ashbringer will play an important role.  Garrosh Hellscream has come from Outland and has established the Warsong Hold in the Borean Tundra (Northrend).  Brann Bronzebeard will be a key NPC leading us to discover the mystery about the origin of the dwarves and probably humans.  This questline will eventually unlock the arrival of the Titans and harbingers as predicted by the guardian of Uldum.  Nerubians and Old gods will be a strong theme in the questlines, and Metzen seems to have slipped we might fight an Old god inside Azjol-Nerub.

Rhonin is finally making it into the World of Warcraft in Dalaran, which is now the Shattrath City-equivalent of Northrend.  Although Dalaran is floating high in the air, players may reach it via flying mount or from the ground like you did in Naxxramas.

The netherdragon taken by Tyri and Jorad Mace in the Celestial Ridge have come to Northrend, and the netherwing physiology is somewhat affecting Malygos … healing his once insanity, becoming more proactive in his role to guard the realm of magic. Malygos has unleashed a war against arcane magic wielders, that’s you mages. This world must be purified.

Wowinsider got ahold of a screenshot showing the Crazy stats of Frostmourne sword. 200 stamina, 100 strength and 150 intellect. 186 dmg per sec. 597-896 damage.  Speed 4.00