someone has to be directly in front of you to parry them and be using a physical move. So yeah I'd try my best to ignore that stat 100%.
For DRK you're going to do the same as with a DPS class and go for Crit/Det. Your main use for Dark Dance would be under Dark Arts for the dodge rate, you'll likely see slim to none on returns from building any kind of parry.
http://ffxiv.ariyala.com/T007
I think this is a decent drk setup for PVP, some things are interchangeable but I did my best for being in the middle of class. (ex: if you have easier access to the greatsword of behemoth king than Deathbringer awoken then go for the behemoth king one.)