With all the negativity around war let's talk about the best part of 4.0!

[Dement]

PLD: 100%*0.8 (ShO)*0.8 (Rampart)*0.6 (Sentinel)*0.6 (Intervention with rampart and sentinel up)*0.77 (Sheltron) = 17.74%
WAR: 100%*0.8 (IB)*0.8 (Rampart)*0.7 (Vengeance)*0.6 (Intervention with rampart and sentinel up)*0.8 (IB) = 21.5% but with 1.45*HP
DRK: 100%*0.8 (Grit)*0.8 (Rampart)*0.7 (SW)*0.7 (DADM)*0.6 (Intervention with rampart and sentinel up) = 18.82% but with 1.2*HP (TBN)

As you can see all 3 tanks can mitigate that much with a PLD's help. actually PLD is the weakest, if you consider the extra HP of the other 2.

I don't see why you would lower your LB gain for this.

If the attack is physical, couldn't WAR also throw up Raw Intuition for an additional 20% reduction from the parry bringing them down to 17.20% and a much larger HP pool.