Ok, so 10% damage reduction is left out because it can't be quantified? It is 10% reduction of incoming damage, Shield Oath is 20% reduction of incoming damage. Maybe I'm not understanding why 10% in one place cannot be quantified, but all of the other pure reductions can be?
On the second:
Your absolutely right, in 8 man content, assuming it calls for 2 tanks, 2 tanks on the same target, you would get both benefits, this is optimal.
Singly, the difference becomes more noticeable, working with math we've all seen:
Assuming both have 6000 HP before stances
Warrior: 6000 * 1.25 = 7500
Paladin: 6000 + 20% dmg reduction = HP/(1 – 0.2) -> HP = 6000/0.8 = 7500
So without heals the effective health is the same, but things change once healing is taken into account. Tanks take 5k dmg over time and need to healed.
Paladin: 5000 * 0.8 = 4000 dmg to be healed
Warrior: 5000 * 0.9 (this is the missing factor) = 4500 dmg to be healed
White Mage Cure II = 1k
Paladin gets 1k * 4 = 4k to recap.
Warrior gets 1.2k * 4 = 4.8k to overheal 300.
That obviously doesn't account for all the other buffs, just Shield Oath vs. Defiance+Path, considering there is little or no reason that after the first 15 seconds of the fight Path should be dropping (or allowed to stay down after jumps and such).
