Possible change to barrier summoner

Just something I thought of while on the oval office.

210 second cooldown. New Active: When activated, grants the user a shield the blocks 130-400 damage and lasts for 3 seconds. After 3 seconds, the shield will begin to decay rapidly at 33-100 health per second. For every 10 health of the barrier that decays naturally, the cool down on the skill is decreased by 2 seconds. Once the shield is entirely gone, the cooldown will start.

For example, if I used barrier at level 18, took 200 damage, and the remaining 200 decayed, the cooldown would be 210-((200/10)*2)=170 seconds.

Of course, the numbers will probably need some changing to make it more or less op, but I think it's a cool idea to bring Barrier back into the game. Yay or nay?