Guild Wars 2

Guardian:
Shield of Absorption – Additionally lowers the cool-down by 0.5 seconds for each attack absorbed and each foe pushed back.

Warrior:
Shield Stance – Additionally lowers the cool-down by 1 second for each attack blocked.

Engineer:
Magnetic Shield – Additionally lowers the cool-down by 1 second for each projectile reflected.

This would make shields much more viable and increase the skill gap for the weapon set, if used at the right time you could potentially lower the cool-down of it by a lot, punishing your enemies for bad focus fire.

in WvW a guardian alone could keep it up with 100% up time then if they are comming with a big enough zerg making it extreamly op as most ranged will get useless as soon as you have a guardian in the operset groupe and not to mention the push back can be used to kill people with if you know how and are the right places on the map