Armor and spell penetration destroys PvP

cwp303b14_ESO

It is my understanding from various sources (reddit, tamriel foundry, these forums) that the tool tips for spell and armor penetration abilities and passives incorrectly state that they allow a percentage of armor or spell resistance to be bypassed.

The reality is that the penetration directly corresponds to the amount of actual mitigation of the target, on a 1:1 scale up to the maximum mitigation achievable by players of 50%, and not the targets armor or spell resistance.

What this means is that 21% spell penetration is a static number that does not scale with the spell resistance of the target. It always penetrates 21% of spell mitigation regardless of the amount of raw spell resistance.

This issue hits pvp pretty hard with regard to armor choice and ability usage.

An example that leads me to believe this is unintentional is the Nightblade ability Marked Target, which allows the caster to bypass 75% of armor and spell resistance (note: that is what the tool tip erroneously claims as discussed above) but, since it applies to actual mitigation, it is attempting to bypass 25% more mitigation than is achievable by a player.

This also leads to a decline in gear selection variation since built in mitigation of armor types (spell resistance for light, armor for heavy) rarely provide actual mitigation and are picked for passives alone.

TL,DR; If the penetration stated in tool tips actually worked the way it reads, as a percentage of the actual armor or spell resistance of a target player, then time to kill in pvp would be increased in many cases, more diversification of builds would develop, and the ebb and flow of combat would be more centered around strategy since AoE would begin to lack the damage needed to kill large amounts of targets with resistances unlike focused single target damage.

Edited for more sensational title