PLDs have no effective way of obtaining or maintaining hate. The only options they have is to use flash which has a very long timer and isnt very effective or to cure them selfs for enimity which uses vast amounts of MP.
As it is PLD is only able to do its job by using the abilities from sub jobs with out a sub job PLD cant gain enough hate to tank, to the best of my knolage PLD is the only job that can not perfom its primary role with its native abilities/spells.
PLDs need an efective way of gaining enimity quickly and maintaining it that doesnt mean having to use certian sub jobs or using vast amounts of armor swaps for enimity, damage reduction, shield skill, haste/damage ect.
In short PLD needs its own version of provoke