Stat Weights

[Themis]

For progressive content Parry can be useful but once the fight is figure out it generally just leads to over heals.

I'd also say that Parry is useful for multiple mob tanking in dungeons/speed runs. There's far more opportunities for it to proc in the same amount of time which should help to reduce some of the damage being taken. Even for a PLD where blocking precedes parrying; it makes a good safety net. In this case, it's worth having a set of gear that maximises your HP and defensive stats rather than a set more focused on DPS. If your DPS can't handle the number of active enemies, the tank adding to DPS isn't going to make much of a difference.

Although, even that depends entirely on which dungeon being run. Earlier ones won't need as much defence because they are lower level anyway.