Hmm interesting... I was told resilience is a stat that counters penetration however I have not yet tested it. resilence is only really used on pvp gear and doesn't really apply much to pve considering this is a fact penetration could be very helpful to put on gear other fact to consider is how often you hit someone then miss them factoring in dodge rate, parry and so on..
But other thing to look into is does a high penetraition get affected by those stats as well or does it mean on a certain chance you hit someone it gives a higher chance to crit or hit them as if they had no armor on level probably also applied to this stat...but we again its unknown if the armor thats affected is physical and magical or just physical I wish someone had more info on this as it would be important and helpful to know which armor is getting affected and if it's affected by dodge rating parry and so on. If it works the way I'm thinking it does I can barely begin to imagine the chaos this stat would do if put on gear and equipment for casters or meele type classes. Problem is not much info is available and if someone knows exactly how it works sharing here would be appreciated.