One of the problems with PLD is the extra time they take to grab hate. I have a 50 PLD and 45 WAR and I can say the difference while leveling the two as pure Tanks is amazing.

Besides the obvious differences among the two tanks, WAR can grab hate a lot faster compared to a PLD. If a PLD hate plummets he will almost always struggle getting it back. A WAR just laughs as he will rarely lose it and if he does he just reminds the mob who's the boss in seconds.

I'm not saying a PLD can't get and hold a mob, but it require more effort than a WAR.