Lots of talk about DRK being the weakest of the 3 tanks.
But havn't seen a ton of discussion about combos and what the benefits of each are.

Having a DRK+War gives you access to Storm's Eye and Reprisal debuff.

While Reprisal isn't always up, it can be up quite a bit.

Apparently they stack, 20% reduced boss damage is nothing to scoff at.

Having a PLD would not give you this, just some food for thought.