Right.

Okay.

This is getting insane.

Let's say you have a high HP tank. Let's say he's wearing full VIT right side, all his points into VIT. That's a tremendous loss of DPS, no? That's damage taken off every single hit you do over the course of the fight, and as the tank you are always dealing damage.

So what does the healer gain from this, hypothetically? Some GCDs, a few of them.

Now what is the question we must ask ourselves?

It's this: Does the healer gain more DPS from those GCDs (not his entire DPS, bare in mind, just those extra GCDs) than the tank loses from wearing full VIT (again, not his entire DPS, but the amount lost from going STR -> VIT)?

Once you can answer that question, you have your answer on which is the superior build.