PLD has block. WAR has bonuses to parry both in Defiance and through Raw Intuition. It's not like blocking or parrying a specific attack has any decision-making about it. It just smooths out damage.

Dread Spikes is an ability that DRK has, historically had, which serves a similar function. Why not merge it together with Blood Price? For the next X seconds, your attacks generate additional enmity. Attacks performed against you restore a minor proportion of the damage back as HP/MP/blood.

Functionally, it's not all that different from "for the next X seconds, your %healing increases and your attacks generate additional enmity" or "for the next X seconds, your block rate goes up, Shield Swipe's recast is reduced, and you generate additional enmity."

You could work out the specifics of how it works for each job, but it's just an example of how you could provide something functionally similar to tank stance without the clunky implementation.