A known change going into BFA is that
Bouclier du vertueux will increase your armor as a % of your Strength stat. This orients
Bouclier du vertueux to be strong against physical damage while losing any value vs. Magic attacks. This change is fine. I'm ok with this change.
A lesser known change is how armor interacts with Block. Currently on alpha, the amount of damage you block reduces as you get more armor. For example, on my 117
Paladin in Alpha quest gear, I have 33% baseline block DR. When I hit
Bouclier du vertueux, it drops to 14% DR.
Now if you consider
Bouclier sacré, a Protection Paladin talent, I gain the ability to roll a block on magic attacks. This has been a tool since WOD for Paladins to counter consistent magic bosses like
Krosus. With the changes to
Bouclier du vertueux,
Bouclier sacré will be the only way to reduce magic damage for Protection Paladins in BFA.
However, when you put both changes together, pressing Bouclier du vertueux reduces the amount of magic damage I could reduce via Bouclier sacré. In a fight like Krosus, it would be better to spec and sit on Bouclier du vertueux charges (or use macros to cancel the aura) than spend them and take more damage.This is problematic and counter-intuitive. Pressing an active mitigation button shouldn't cause me to take more damage than I would have if I didn't press that button. No other tank has to deal with an interaction like this. It will lead to /cancelaura macros where am I pressing
Bouclier du vertueux for damage then canceling it right away to maximize the damage reduction from
Bouclier sacré. Imagine having to do
Krosus but having to /cancelaura
Bouclier du vertueux constantly as to not take more damage than we should be and maximizing damage/threat.
There will be points during Mythic bosses where, I'll be thinking, "Here comes the magic hit, let me click off my
Bouclier du vertueux so I can increase my damage reduction vs magic." Tanking shouldn't work that way.
/cancelaura macros for Active Mitigation Buffs against spell damage is not good gameplay and changes should made to avoid this situation.