After 1 (arguably 2) expansions what is square trying to achieve with WAR (and PLD)?

[Absurdity]

They complained about DV/PoA as well, which was why SiO was reworked into a completely new action mid-expansion. I think that was the first time in this game's history that the devs threw out a newly added action and replaced it with a new one simply because a job's players demanded something more powerful.

SiO wasn't really replaced mid expansion. It was what, 1 patch later? And SiO was a bit of a special case because it simply didn't work half the time.
If they give you a debuff remover that should work even while stunned, but often it just does nothing, it's an inherently flawed ability.

And the funniest part was that 4.0 SiO would've been perfect to remove the pacification from Berserk, but they removed said pacification at the same time.

The bonus reflect damage is the original effect, and in my opinion PLD is the only one that should have a flat 30%. Every other tank should have something suited to their flavor. I.e. WAR having 10% mitigation with 40% max HP increase and the thorns effect. But the devs are too lazy for that or to remove the thorns effect.

The problem is also with certain mechanics, take the Abyssos bleed busters for example. 10% mit and +40% HP for 15 seconds is nice on single hit busters, but when you're taking damage over time and that damage is based on how much damage the initial buster did, suddenly you're taking way more damage and your HP buff does nothing.
We saw it already with Bloodwhetting and ToB to a smaller extend because they provided either low flat % DR or none, but Paladin drew the really short stick with bleeds completely ignoring Holy Shelltron's block.