You're neglecting another relevant tank trait - "unhittability". Which is understandable because this gets overlooked by most people.
This measures how frequently a tank is able to avoid suffering a full hit from a boss based on the boss' hit table. This is calculated by factoring in the tank's avoidance, including the boss' miss chance, and the tank's block chance. Near BiS-ish levels of gear, this figure for Paladin and Druid tanks works out to be, if I recall my numbers correctly, somewhere around 95% for a Bear and 90% for a Paladin. In other words, 90-95% of all incoming hits are either fully avoided, or mitigated by an amount equal to your Block value, which is usually somewhere between 2.5-3k for a BiS Pally or Bear, or between 6-8% of an LK melee swing. The fact that this kind of mitigation is up near 95% of the time bestows it with EHP-like levels of reliability. With regard to tanking purposes, this therefore becomes a very relevant metric that's almost on par with the aforementioned EHP talents WotN and AD.
I bring this up because while Pallies and Bears are terrifically strong in this regard, Warriors are much less so, being only 72% or so unhittable near BiS. The reason for the gap between Warriors and Paladins is because Warriors don't have a Holy Shield equivalent. Warriors are instead "compensated" by having the ability to critically block, so when mitigation occurs, it's more significant.
DKs, not being able to block, are the most shafted in this area, with all their unhittablility coming straight from avoidance. For DKs most of all, this is not something that can be counted on for mitigation purposes the way it can for a Pally or Bear. So to crown DKs as uncontested best main tanks is misguided.