I'm working on an imperial tank that uses Blazing Shield. The tool tip is a bit misleading the strength is increased based on the number of targets in the area when you cast it...not sure if there is a cap on it yet. So my build is 65k HP in cyrodiil. In a 1v1 fight the shield strength is ((65000 × .3) × (1.24 for bastion + .04 for 1 target in range) ÷ 2 for cyrodiil nerf = 12,480. Very nice shield. And it explodes for 6,240. Jump into a zerg ball and have a conservative 10 people in range ((65000 × .3) × ( 1.24 + .04 × 10) ÷ 2 = 15,990 detonating for 7995 So I would say it's still a good skill if you spec LOTS of health.
Imagine emp with this build in a zerg ball ((65000 ×1.75 emp buff) × .3) × 1.24 + .04 ×10) ÷ 2 = 27,982 shield and detonating for 13,991.