I have a little information to share to you about armor reduction

When Ive found out what is the equivalent value of armor reduction in damage, I realize that we must not focus only in AOE skills/disables/nukes/chain stun but also in armor reduction

In every -5 armor reduction you made, your damage increase by 33%

so if Lanaya has a desolator (-6armor, desolator +60dmg), Meld (-8armor, +200dmg), base dmg let say its 80dmg)
total = -14armor ~ 100% damate + 340

its 640 damage! in a single hit if the enemy hero is around 0-10