I did say it the wrong way.

What I meant is more like: WAR's defensive capabilities are strong because Holmgang has such a short recast cooldown compared to the other two tanks. It's just lots of people complain how Vengence is ten light years ahead of Shadow Wall and that's why DRK needs a buff.

Overall, I don't believe that any of the tanks are OP right now. If I had to rate them for overall usability, PLD would be the strongest overall, followed by WAR, and then DRK bringing up the rear. This is because I tend to greatly value the party support that the class brings. But none of them are unplayable or unusable. They are all very capable.
Pretty much this. All three tanks are really well balanced right now. Not perfectly balanced, so there's still a "worst" tank, but each one have their pros and cons.

In my opinion:
- WAR has the highest damage output, and a party-wide shield that you can abuse to boost the limite break gauge.
- PLD has the worst personal mitigation but the best team support.
- DRK has the best personal mitigation and about the same damage potential as PLD, but almost no party support.