I don't think you pay enough in raw ad/damaeg when buying armorpen

50 ad & 15% phys damage increase Its quite alot 50 ad and reduces healing/regen also quite an increase in damage vs high sustain targets

50 ad is average but not bad

60 ad is pretty good

overall with items like this your damage loss isn't that big especially if you stack them the shred and flat pen improves your damage vs squishies and the last-whispers increase damage vs high hp high sustain on top of it

overall when compared vs other high ad items the damage vs squishies is rather similar if not better.

vs tanky targets who grab a good deal of armor though your damage when compared to other high ad items goes through the roof

there really isnt a reason not to stack this since there are barely any trade offs

gives high damage vs squishies still, but damage vs tanks explodes, gives you all the mobility you want as well as cdr.

i think stacking pen items is too powerfull with too little trade offs

my proposal to fix it flat pen needs to apply before % pen to reduce flat pen and % pen synergy. This helps split up their niches as well making flat pen the anti squish go to and % pen the anti heavy armor go to.

Then the ad on the items, especially the % pen items, should decrease. black cleaver used to have 40 ad it should be reverted to that last whispers also should give 40 ad.

i think a trade off in choosing whether or not to be effective in killing high defense targets vs squishy targets is healthy and this is currently not the case.

eventually come lategame a full critbuild with just a lastwhisper will outscale in damage but then we are talking about 6 item builds meanwhile for the rest of the game the pen stacking is just stronger vs everything.