IMO, better than perceived, yes. But the effectiveness of armor reduction would already be showing up in cruci timings, so it’s really just a perception change.
As TQFan mentioned, the biggest takeaway is that the relationship between phys resist and armor is “stronger” than before, so it’s more sensible to invest in both rather than just stack one at the expense of the other
I got what you meant now. Yes, Armor absorb bigger % of damage it deals with.
But also Phys Res now reduces bigger % larger absolute portion of damage it deals with. 
I think it’s enough for me for today.
On second thought, I just took a look down the list of Bosses and Nemeses on grimtools and very few have above average base armour. Unless I missed one somewhere or there’s an armour buff that someone casts on nearby enemies, it’s just Callagadra, Ravager, Mogdrogen, Iron Maiden and Ulgrim. Which kind of surprises me, I would’ve expected certain Bosses like Azaleon, Steward or the Ruined Temple trio to have high armour in addition to them having high Physical resistance but they don’t.
Other than that, I suppose there’s the chance of enemies equipping gear with +% Armour affixes and mutators to lower/increase player armour or lower enemy armour.
Would explain why armour reduction isn’t useful in Crucible then - only Maiden is a concern and mutators for enemies can only lower their armour instead of raising it.
it could be simplified to:
your armor value is divided through (1-physical resistance) and the remaining damage is than affected by the physical resistance (assuming 100% armor efficiency).
X * (1-physical resistance) - armor = (X - armor/(1-physical resistance))*(1-phyiscal resistance)
It makes phys res more important if you have a lot of armor because it means that leaving its value in 0-20 will result in increased damage input after mob’s RR (so nk armor might not save you as it usually does) and because after a certain point its easier to increase % phys res than stacking flat armor.
It also makes full absorption armor even with low value more important for characters with 80%+ phys res. The obvious problem here is that there’re very few builds with such phys res value.
Does it?
Pet builds can easily get high amount of Physical Resistance (especially conjurers). Yet, I have never bothered with Armor or Armor Absorption and whenever something would end up killing me, it is always some other form of damage.
So, personally, I have never considered it important.
Note: I understand that with Zantai’s revelation, armor’s value just rose up. But other than against specific bosses that deal almost exclusively in physical damage, the value of armor in comparison to other defensive measures hasn’t changed in my eyes atleast.
Note 2: Could also have some bias in my observations due to being a pet build and not having to tank enemy AA, resulting in most of the incoming damage being spells and AoEs, which tend to be non-physical.
I’m glad all this time, my standard for a build is to have at least 2k armour and 20% physical resistance. Those 2-3 Bloodied Crystal, Titan Plating, Hound devotion are not going to waste 
Awesome to new faces keeping theorycrafting/testing alive.
Given that phys res does apply first, it makes phys res so much better since it’ll do such a better job at reducing big hits.
My untested assumption would be it would depend on the primary attack. For big ass cadence hits - not so much. For something like EoR? Definitely.
Depends on what’s killing you. Assuming you’re getting chunked by a 10k phys attack.
With 40% phys res, 1k armor —> 5k damage received
With 20% phys res, 2k armor —> 6k damage received
I wouldn’t fixate on absolute numbers but rather look at the class you’re using. If you can stack armour far more easily than phys res, getting that 3% phys res node on something like sailor’s guide will go a much longer way.
To illustrate my point:
Assume incoming 10k phys damage.
To reduce that to 5k, you’d need 5000 armor with 0 phys res. Alternatively, you can achieve the same outcome with 10% phys res + 4K armour.
So here, 10% phys res = 1000 armour.
Again, the value of each defensive layer is very situational, with phys res becoming more and more valuable with larger hits.
Personally, I would value mitigating big ass one shots simply because you can rely on things like heals and circuit breakers if what’s taking you down is a million tiny cuts.
EDIT: armour also doesn’t reduce internal trauma
I don’t quite understand why this would be the case. IMO, value of phys res went up because it’ll be negating a greater proportion of the incoming damage.
100 phys atk, 80% phys res & 20 armor = 0 dmg, right?
But if armor applied first, 16 dmg would still go through.
So, from my perspective, the phys res is still doing the same while Armor apparently does more than it was thought to.
Just a different way of looking at the same thing I guess.
But what does 100 damage?
Let’s say 500:
80% res + 20 armor —> 80 damage taken
Flip the order around —> 96 damage taken
IMO, phys res becomes more valuable very quickly
100, 500, 10k. Can take any arbitrary value. Don’t think that changes anything for the calculation.
What I am trying to say is that while 80% phys res will always block 80% of incoming physical damage, whether that 20 Armor blocks 20 damage or lets that 16 phys dmg slide through would depend on the order in which armor and phys res are applied.
So, on a build with 80% phys res, 20 Armor would effectively block 4 damage if it was armor first and the full 20 damage if it was phys res first. So, keeping the phys res at 80%, Armor gained 5x value.
Doesn’t matter which one is more useful mathematically. Practically it doesn’t change much imo. Casters using caster armor still won’t be able to reach 3k. Tank soldiers using heavy armor still reaches 4k armor easily. People won’t suddenly start getting 100% armor absorb on non soldiers because there are other components on thst chest armor that are more valuable depending on where you’re playing.
Tho it’s great that we’re getting more clarification on game mechanics.
And offensively, the same should apply to physical resist reduction - as a multiplicative factor before armor comes into play. Therefore directly influencing the amount of damage which is not affected by armor at all (another way to describe it: physical resist reduction can also be seen as a kind of armor reduction)
You guys are repeating 1-1 what we’ve already discussed 
This is just a perspective as you said yourself because I can say the same but arguing for Physical Resistance:
"What I am trying to say is that while 20 armor will always block 20 of incoming physical damage, whether that 80% Phys Res will reduce Incoming damage * Phys Res points of damage or just (Incoming damage - Armor) * Phys Res points of damage, would depend on the order in which armor and phys res are applied.
Aye, 
I think what’s being discussed matters more for iron giants because you can prioritise devotions/skill points accordingly.
But you’re right to say that the argument is moot for casters
to expand this thought a bit
old (assumption how it works):
max(0, damage - armor)(1-PR) + min(damage(1-armor absorption), armor*(1-armor absorption))*(1-PR)
case 1: x > armor
(x - armor)(1-PR) + (armor(1-armor absorption))(1-PR) =
(1-PR)(x - armor + armor(1-armor absorption))
case 2: x <= armor
x(1-armor absorption)(1-PR) =
x(1-PR)(1-armor absorption)
new (corrected version):
max(0, damage(1-PR) - armor) + min(damage(1-PR)(1-armor absorption), armor(1-armor absorption))
case 1: x > armor/(1-PR) or x(1-PR) > armor
x(1-PR) - armor + armor(1-armor absorption) =
(1-PR)(x - armor/(1-PR) + armor(1-armor absorption)/(1-PR))
case 2: x <= armor/(1-PR) or x(1-PR) <= armor
x(1-PR)(1-armor absorption)
When comparing old and new, physical resistance can be seen as armor buff or debuff, as it is possible to replace armor/(1-PR) with e.g. armor* (“effective armor”) and the formulas in both cases (old / new) are (beside the effective armor value) identical. Likely one of the reasons why Maul does less than expected - with high physical resistance reduction, the effective armor was already lowered.