DRK at least has the option of using Unmend for a couple GCDs when they bottom out (or Abyssal Drain, or Dark Passenger, or Plunge), while PLD has COS and Shield Swipe (and not even Swipe if they're OT).
It's trivial for a PLD to go dry on TP, and it's the only tank with no way to get it back without begging the NIN. That's why the suggestions I made way, way back on page 1 all include ways for PLD to recover TP that aren't straight clones of Equilibrium/Purify/Invigorate, and work with the existing skills PLD already has.