% penetration items and black cleaver need reworked.

Completely, there is no reason a % penetration item should increase your damage by 35% against armored champions and STILL have a nice chunk of offensive stats to K.O. a squishy.

They need reworked to have the offensive stat COMPLETELY removed, and granted % armor and magic resist (Respectively) to each upon damaging them. Flat penetration items can stay AS IS, with the exception of black cleaver, which will either be removed or reworked.

Having no offensive stats means this is no longer a staple item for carries, freeing them up to build something that will benefit them more. This also means it will be a pick on supporting and tank champions to reduce their defensive stats so their allies can hit harder.

Having it be something like 3000g, 5% BONUS resistance shredding, stacking over 4 seconds (up to 4 times for a total of 20% BONUS resistance shred)[This does not stack if multiple of these are purchased on a team, it will still be a 20% shred, but is easier to stack], then lingering for x seconds after achieving full stacks, coupled with some NONE OFFENSIVE STATS will make this a good pick for tanks or supports if you see the enemy is building heavy armor or magic resist against your bulk damage.

This also means the WHOLE TEAM has more damage, but you need to commit to this item.

I think this is a great idea, but has some nooks and crannies, though this is what riot's team is paid to figure it out.