As a defender, I find this idea is terrible with just being able to shoot out due to the overpowered potential. An alternative is only letting primaries shoot out of the bubble with a 25% damage reduction, but you can also shoot allies and give them an overshield. To prevent op potential with the shield, as soon as you shoot someone it gives them a 45 second timer that prevents them from being buffed with the shield again. This overshield would be around the same as blessings of light, but cannot be stacked with blessings.