Quotes from Ghostcrawler, blizzard poster:
We have been doing some more tests on DK tanking, this time especially on raid bosses. We think the DK design has some limitations, which weren’t showing up as much on tanking 5-player dungeons.
Specifically, as many people suspected, the death knight really suffers when attacks fail to land, especially opening attacks. Having a Plague Strike dodged or parried can throw off an entire rotation, eventually leading to bad Obliterates because both diseases weren’t up at the same time. Missing attacks is a fact of life for all tanks since it’s hard to stack hit and expertise along with mitigation stats. However, existing tank classes have mechanics to let them “burn off rage” (or mana) to make up for those bad strings. The DK plays more like a rogue who can’t get enough combo points in play. This had a deadly effect on DK threat generation, which just didn’t compete with that of other tanks.
We didn’t want to just solve this with more free expertise because A) that has major PvP ramifications, and B) the death knights would start to hate expertise on their gear.
Instead we are making some fairly big changes:
1) Blade Barrier now procs when your Blood Runes are inactive. While the initial implementation of this ability was fun, as we added Death Rune mechanics it became harder to use, and the fast recharge on missed attacks made it even harder. Now it should be up almost all the time.
2) We also found a bug where a naked, untalented death knight only had 2.5% dodge instead of 5% like warriors and paladins. With these two avoidance changes, death knight survivability should be very close to the other tanks, recognizing that avoidance is more dangerous than mitigation for a tank. As an aside, death knights, warriors and paladins currently mitigate a similar amount of damage, and druids may very well be mitigating too much.
3) Frost Strike can no longer be blocked, dodged or parried. Frost death knights were losing too much potential damage and threat when Frost Strike failed to connect, putting Frost tanks in the awkward position of wanting to skip Frost Strike and just use Death Coil.
4) We changed Rune Strike completely. It is now mostly a tanking ability meant to dish out high damage (and therefore threat). Rune Strike can only be used after you dodge or parry an attack. It affects the next swing, so it doesn’t compete with global cooldowns and can be spammed to some extent. It hits for 200% weapon damage (remember 100% of that is the white swing you lost) plus a percentage of AP. It cannot be dodged, blocked or parried, and costs 10 runic power (for now). Think Heroic Overrevenge. :)
5) I think we already announced these changes, but just to get them all in one place: Bladed Armor went back to attack power. It was changed only to match the warrior talent, which we changed back. Death and Decay got a decent threat boost to get it closer to the realm of Consecration and the new Thunder Clap.
- Rune Strike is going to be great now while leveling, this will be nice boost for all specs. It was high time they took this ability off the global cooldown, because seriously, extra global cooldowns is something Death Knights just don't have :P
- The change to blade barrier makes it even better now, to the point where I think this talent should be taken no matter what spec you go for. It's basically a guaranteed +10% Parry for only 5 points now, it's hard to pass up on that.
- I also like the Frost Strike change, it's a step in the right direction to make the frost tree useful, at least for tanking.