Honestly, I question the value of parry as a whole.

The only information I can find regarding parry rates is:
http://valk.dancing-mad.com/?page_id=179/#Parry

This is old stuff, and might not be up to snuff, in fact I kind of know it isn't. I need to test the numbers on low levels of parry (shown in the graph), but there's no way I'm getting a static .076% chance to parry per point.

I have ~532 parry on my War iirc, and my parry rate sits somewhere around 20% from my own little testing runs. So my best guess, pending verification of the low levels of parry numbers, is that there's either a huge drop off from the benefits gained per point of parry after ~300 points, or its worth almost nothing.

The scaling of Dex in relation to parry can only be worse...