Ahh Death Knights...you either hate them, or they're your new main. I fall into the latter. ^_^ I came back to WoW for WotLK primarily because I wanted to try the Death Knight; WoW's first Hero class, and one I had personally hoped for as a Horde exclusive, has lived up to my expectations. From an amazing starter experience, to an unstoppable solo powerhouse while leveling up, to a monster in PVP BGs and WG, to a badass tank; I've had my fun. But let's talk about the future...
New Rune System
The biggest change for DKs in Cata is the revamping of our Rune system. On live now, both runes of any given type (Frost, Blood, or Unholy) refresh at the same time; in Cata only one rune of each type can refresh at one time. This will essentially half the frequency with which we are able to use abilities, barring some front-loading like a rogue or kitty. To compensate for that, Blizz has given us Runic Empowerment. Whenever we dump RP, we have a 45% chance to activate a random rune. The other change (particularly for tanks) is that Rune Strike is no longer 'Next Melee' and is instead an instant strike. This will give us something to do when all our runes are cooling down, and hopefully proc one back for us. Here's a blue post with some more discussion about Runic Empowerment, and it's affect on DPS rotations.
As mentioned above, Runic Empowerment is the first of our new skills; Dark Simulacrum is another. It's similar to spell reflect except that it acts as a debuff on the target, triggering when they next cast a spell and copying it's effect for the DK. We also get Necrotic Strike, a PVP skill that absorbs healing that would be done to the target. This is sort of a replacement for the old Plague Strike functionality that removed HoTs. Next we have Outbreak, a 1m cd that applies both of our diseases to a target and consumes no runes or RP. I like this one, because it will help me still be able to drop DnD, get both diseases up, and throw a DS on pull. Finally we get Festering Strike, a B/F skill that extends the duration of Frost Fever, Blood Plague and Chains on the target by 6 seconds. I'm not sure how much use that'll see outside of PVP, but we'll see.
Next time, I'll talk about the talent changes coming for Cata.