How to make Courage of the Colossus a better keystone

Right now this is COC (we pronounce it co-ck)

Gain a shield for 20 - 190 (based on level) (+ 7% maximum health per nearby enemy champion) for 4 seconds after hitting an enemy champion with hard crowd control.

Right now there are champs like Riven and Leona that really abuse COC in the early game. Instead of the whiplash balancing that we have come expect from Rito, I hope Riot considers that in the new season's masterys there is a lot of % damage in there, and tanks are tanking with paper armor right now. Something needs to be done about the "Damage Creep" to help tanks to be more relevant mid and late. Tanks do not need damage, but tanks should be allowed to survive and to do our jobs.

Here is my idea to fix COC: Gain a shield for 20 - 190 (based on level) (**+ 14% bonus health **per nearby enemy champion) for 4 seconds after hitting an enemy champion with hard crowd control.