Tanking is kind of broke altogether. Which is why we have this problem in FFXIV, its just not balanced at all, leading to a War out preforming a PLD in every way. This could be one of those maybe it will get fixed in 2.0 but who knows.

They could fix it by doing what they did in WoW. WoW they have 4 classes that can tank, paladin, death knight, druid, warrior. All the classes that can tank have tanking stances, while they are in their tanking stance, basically means their dps is much lower compared to dps classes, the survivability is much higher then everyone else, the threat they generate through damage is 500% higher. Tanks are pretty balanced so that you can take any of the 4 to do raids with.