Is Northrend not a part of Azeroth? Would Deathwing not be as interested in burninizing Northrend as he is the other two continents?
If a future patch for Cata does not include a cinematic wherein Deathwing rockets into Northrend to melt Fordrangon from his ice bock atop the Frozen Throne and pit him against the players in an awesome raid encounter, then Cataclysm falls flat on it's face. Honestly, what have we seen that indicates Deathwing is a destructive madman, aside from the Cata cinematic? Most questlines don't even relate to him directly; you'd think that in a world recently torn apart by a giant dragon you'd have a majority of tasks aimed at quelling destruction or recuperating.