Riot I think the current armor pen is to weak. Math included inside.

WARNING: LOL history lesson with a suggestion inside

Back in preseason 3 flat armor pen was changed to apply after % armor pen. (aspplies to MR as well)

For preseason 6 we now have % bonus armor followed by flat pen.

I will include the general amount that you might see on items Youmuu's Ghostblade and LW or a current LW final item MR/LDR.

Season 1 and 2 (flat applied before % penetration) (150-20)*(1-.4) 130 *.6= 78 armor

for season 3 through 5 (flat applied after % penetration) 150*(1-.35)-20 97.5-15=77.5 armor

Currently on live(% bonus armor reduction before flat penetration) 75+ 75*(1-.4)-20 55 + 45 = 100

As you can see based on this quick example the current armor pen system is not even really comparable to past seasons. The current system does start to fair better against really high armor targets but it is still lacking when compared to what has been in the game be it season 1 or season 5.

RIOT if your goal is to make assassins only want flat penetration then I would suggest changing back to how it was in season 1 and 2. This in turn would make getting LW reduce the value of flat armor pen by 40%. It would likely not break marksmen doing this as well considering that it would still be fairly comparable to what has been around for season 3 through 5 and much easier to balance then turning the whole game on it's head with the current system of only effecting bonus armor.

Yes I am saying that the uneffected 80+ armor of some champs is making them overall strong. This includes champs like Mundo (26.9 – 86.4 base armor), Rammus (31.4 – 104.5 base armor) and Malphite (28.3 – 92.1) among others.

YEs I am admitting that making LW items only effect bonus armor is not enough if it is kept at 40%.