The whole armor system is pretty much ResidentSleeper. Especially on POTD.
Stacking armor, especially when using some spells like the RANK1??? wizard spell that gives +3 for 60seconds+ is too good too fast. If you overcap enemy pen by 3 points you literally become invincible. Its pretty stupid. Meanwhile if you dont go over pen, armor does nothing. Literally nothing.
On the other hand the game basically forces you to gear up really early (i have seen guys with 10 armor regularly even early on), makes low pen weapons effectively useless (e.g. Greatswords) and while you technically CAN reduce armor through other means, there really arent that many good spells/abilities for doing that in the game. Basically just the Chanter spell at rank 3 and the Cipher spell later on.
Theres a rank 7??? druid spell that does it as well i mean WUT? rank 7? reduce by 2? can miss?? limited duration? Or you know... you could just get a mace with the mace weapon ability instead of spending your rank 7 spell...
There is also absolutely no payoff for stacking penetration since getting twice the enemies armor in penetration is pretty much impossible on POTD (maybe some random instakill trash like the devoted slaves idk) and even if it was theoretically possible it gives 30%?? bonus damage?
What this means is you always want to have your penetration exactly equal to the enemies armor since you probably pay somewhere else with stats/abilities otherwise.
Why not just make armor give a consistent %damage reduction that is reasonable (not 70% instantly for 3 points over pen). The breakpoint is extremely annoying to play around and on the defensive end makes characters invincible way too fast. While it has no impact at all before going over that breakpoint as long as you dont run around i a shirt. (And even then its only 30% bonus damage...)