WotLK Classic Blood Death Knight Stat Priority

1. Defense to 540;
2. Hit to taunt cap;
3. Stamina;
4. Expertise;
5. Dodge.

While Defense rating does provide some additional avoidance, its primary function is to mitigate your chance of being crit. The 540 cap is absolutely necessary before entering a Raid because being crit by a boss can often lead to you being either killed instantly or taking an unhealable amount of damage. You must avoid being crit at all costs, making hitting Defense cap your highest priority.

Thanks to the Glyph of Dark Command you do not need a ton of Hit Rating, but you do need enough to be Spell-Hit-capped with the glyph active. Taunting is a huge part of tanking; while you may not be using this spell rotationally, being 100% certain your taunt will land can be the difference between wiping or killing a boss.

Death Knights lack the ability to block or mitigate damage in a consistent way, so a large health pool is necessary as you will oftentimes be taking the entirety of the damage dealt by abilities. Death Knights also scale extremely well with gear, both in a larger health pool and damage dealt resulting in larger amounts of self-healing, so the higher your total health pool is the more you are likely to benefit from the self-healing provided as a Blood Death Knight without overhealing yourself.

Expertise ensures that your attacks are not dodged or parried. While Death Knight does have Rune Strike, it is crucial that your Runes are not wasted by being used on an attack that is avoided.

Dodge avoids all the damage that would be taken by an attack and thus is extremely important when it comes to surviving. It is important to note that you cannot depend on getting lucky with dodges so other defensive stats are a bit more valuable, as consistency of damage intake is the key to understanding how to handle each encounter.