Originally Posted by
Obsidian
With a Holy Shield +1/Allagan Round Shield, Bulwark is only an effective damage decrease of ~25% on physical damage only.
Assuming a block rate of 28% with Holy Shield+1/Allagan Round Shield (10% base block rate plus 1% for every 10 points of Block Rate on the shield), and assuming the best case scenario of Bulwark being additive and not multiplicative, we have an effective block rate of 88%. Assuming a block strength of 28% (it's reasonably difficult to get enough STR to hit this), over 1000 hits for 500 damage each, Bulwark will mitigate ~25% of the damage done (880 blocks that reduce each hit by 140, so 123,200 damage blocked out of 500,000 damage total).
So effectively, Bulwark is 5% less mitigation (at least, because again, it only works on physical damage) with a 60 second longer cooldown than Vengeance (and hilariously, it's 15% less than Sentinel with the same cooldown), which makes it barely more effective than Rampart for twice the cooldown and half the duration.