Two weeks ago, I posted a comparison of tank dps. You can find those results here. This is the present situation, two weeks later:
As you can see, not too much has changed. PLD seems to have the potential to edge out WAR on V2S when both jobs are performed more optimally (possibly due to the high uptime and relative lack of movement), but WAR has a fairly consistent advantage when it comes to dps across the board.
I wish that I had done a formal comparison of the tanks on the Ex Primals prior to 4.05, but I remember that prior to the WAR buffs, WAR and DRK were on a fairly even footing. The Storm's Path potency buff does not explain the difference post patch. I think the biggest factor here is that, by removing the stance swapping costs on WAR as well as the costs for IR/Unchained while leaving all of DRK's stance swapping penalties intact (not just the MP cost, but the costs associated with truncating BW/BP), the devs have created a fairly sizeable imbalance between the tanks. The gap has slightly narrowed since two weeks ago on earlier fights as tanks' stance uptime drops to zero, but it's much wider on later fights.
I don't think PLD is the problem here. It's actually sitting at a fairly healthy middle ground.
I know that there are a lot of factors that influence players' subjective perception of difficulty. If someone only played WAR in HW, with its relatively simple resource management, I could see how they would struggle with the pre-4.05 changes. In truth, from following the dev interviews pre-SB, it sounds like the stance cost was intended to prevent WAR from being too overly flexible relative to the other two tanks (i.e. to bring WAR into line with everyone else following HW's dominance.)
But after 4.05's revision and reversions, I really don't see it. If anything, looking at how dps varies with percentile, there's a much smaller dps discrepancy between playing WAR skillfully and playing it poorly. Which was sort of the point of the job system changes: to narrow the performance gap between players. Objectively, as far as the performance data goes, it appears to be the least punishing tank.
I think if you stack more WAR buffs on top of this situation, you're going to end up with a very unbalanced meta, especially if Shake it Off's planned rework ends up significantly bolstering WAR's raid utility on top of its dps advantage. As it is, nothing has really changed from HW, except that you've just swapped in PLD for DRK for the second spot.