So far from what I heard in the GIGA Live Stream, this is the official info straight from what Frank Pearce or the Cinematic revealed:

  • Players may face Arthas with a level 80 Cap
  • New Arenas
  • New Battlegrounds
  • Siege Weapons
  • Buildings that can be destroyed with Siege Weapons
  • Inscription profession can permanently enhance abilities
  • Plans for 5-man, 10-man, 25-man raid dungeons.
  • Deathknight Hero Class (Confirmed) – We have all been following into Arthas’ steps seeking revenge on the Burning Legion and all our enemies.  We have now become Deathknights ourselves.  Arthas the Lich King has laid our path, and has planned all along how to scour all life from Azeroth while we were busy in Outland.
  • Monster I saw in the cinematic: Wendigo – an man are they huge! However, if you read World of Warcraft RPG: Lands of Mystery—this huge creature could be one of the Storm Giants from Ulduar … gasps! (Unconfirmed).