Because I had a bit of time, I quickly threw together everyone's favourite thing, a graph that shows how effective the mitigations actually are:
https://www.desmos.com/calculator/ejv2rhttny
X-axis is Max HP, this is just so that you can compare between different Max HP values, and allows the scaling of TBN
Y-axis is the damage done after mitigations and heals.
Black line is Dark, Blue is PLD/GNB (virtually the same graph for each anyway), Orange is Warrior and the Purple line is TBN with a 10% mitigation ontop.
To use it, set the variable 'D' to whatever damage you want the incoming attack to do, go across the X-axis to the Max HP you want to compare and go up. The lower the line, the more damage you have mitigated/healed.
This should highlight just how strong Bloodwhetting is compared to the other mitigations. As a comparison, Bloodwhetting and Holy Sheltron will mitigate about the same if the attack does ~216,000 damage.