How many ways can a PLD draw hate? A few buffs from other jobs, full enmity merits (not the best choice if you ever plan on leveling other jobs that need less enmity). Provoke, which sadly does just about nothing anymore, and it is not even an ability that PLD know naturally!

Come on guys. Work with the PLD's here. How about a job ability that gives the old classic Japanese *tugs on an eye and sticks out the tongue for a raspberry*. Might be too comical, but if it worked, I'd spam the snot out of it whenever possible.
So, let's say PLD gets all this stuff you want and can hold hate off of every job in the game, consistently. Then what?

As long as the mnk can still hold hate off the mage and not die, using the mnk to tank is going kill mobs faster than using the pld tank.

There's still no reason to use a pld.

Until a monk can't hold hate off a mage in a situation a pld can or a mob comes up that mnk can't survive against where a pld can, there's no reason to use a pld tank, regardless of whether or not they can generate more enmity than a monk.