Guardian keystone add on cool-down Reduction

I feel that Guardian needs a cool down reduction system similar to Arcane comet to get a better use out of it.

Cool-down reduction: Marking( guarding) allies with spells you cast: 5%

_ this cool-down won't proc on Allies you already marked with a targeting spell until the current one wares off. __

When allies you marked take damage while : 0.5 secs (0.25 secs marked by spells) per 1% heath lost.