Cataclysm Changess Hmmmmm?

Outbreak (level 81): Outbreak infects the target with both Frost Fever and Blood Plague at no rune cost. This ability allows death knights to apply diseases quickly when they are switching targets or when their diseases have been dispelled.

Necrotic Strike (level 83): Necrotic Strike is a new attack that deals weapon damage and applies a debuff that absorbs an amount of healing based on the damage done. For context, imagine that the death knight can choose between doing 8,000 damage outright with a certain ability, or dealing 6,000 damage and absorbing 4,000 points in incoming heals with Necrotic Strike -- the burst is smaller, but a larger overall amount of healing would be required to bring the target back to full health.

This ability is meant to bring back some of the old flavor from when death knights could dispel heal-over-time (HoT) effects. It also gives the class a bit more PvP utility without simply replicating a Mortal Strike-style effect.

Dark Simulacrum (level 85): The death knight strikes a target, applying a debuff that allows the death knight to copy the opponent's next spell cast and unleash it. Unlike Spell Reflection, Dark Simulacrum does not cancel the incoming spell. In general, if you can't reflect an ability, you won't be able to copy it either.