I have one group were main focus is using pure AOE (at least on all non-boss mobs). The group consist of two priests casting Holy novas and two mages casting Arcane explosions.

Now which tank has best capability of trying to hold aggro of those slaves:
a paladin using consecration and righteous fury OR a death knight using frost presence and death'n'decay (with additional damage dnd glyph). Which of these two will generate highest aoe-threat?