ZOS,
- max level player has innate penetration of 7920.
- 5 light armour gives spell penetration of 4884
this = 12804 penetration.
if I add a single sharpened sword (7%) then it is 13700. 7/7 light armour is now completely ignored.
If I add elemental drain (debuff by 5280) then my penetration is effectively = 18980
Or, unbuffed medium armour is now completely ignored
If we now consider a heavy armoured tank who has 30k resistances, they have an actual working 11020 mitigation. If we assume that you get 1.5% damage reduction per 1,000 mitigation (roughly accurate) then that 'tank' is mitigating about 16.5% of the incoming damage.
16.5% of the DPS meta that we currently have.
I don't know about anyone else, but that seems pretty darn low to me.
I do wonder whether we might benefit from the removal of player innate penetration from Cyrodiil.