I dont know if this will solve anything but...
What if cleaver stacked 2x as many times as it did now, shreading half the armour per stack (adding up to the same amount at max stacks) But ranged champions stacked 1 time per hit and melee stacked 2? this would change nothing for champions like Darius, Garen, Illaoi, Fiora etc... but it would mean Champions like Miss Fortune and Lucian would need to wait much longer until they got its full effectiveness :/
Huge nerf for this guy, he basically got designed around Black Cleaver.
He is an intended user (Juggernaut) and synergizes extremely well with it.