Holy shit lethality is op.
So I was in the shower and thought how much penetration can you get when you combine %pen and lethality. After running the calculations the results I found were disgusting.
Lets say a tank has 90 base + 200 bonus armor = 290 armor and 
has 
and lethality reds and quints, and the 7% armor penetration in the ferocity tree.
The tank loses 87 armor from black cleaver so down to 203 armor (113 bonus).
Lord dominiks ignores 51 armor so down to 152 armor.
The mastery removes 11 armor so now the tank has 141 armor.
Lucian has 74 lethality so the tank now has effective 67 armor.
That is a 134% damage increase just from shred and penetrarion.
