Help me understand mechanics - Builds, Talents and Class Mechanics - Hunter Forums

My armory is here:  Niika of Moon Guard

Deathbringer's Will dropped and I won it.  Slipped into my arpen gear, and noticed a 1,000 point dps loss for the night.  It proc'd like half the time for me.  I changed back to my Herkumi War Token and my agi gear after almost 2 hours, and handed off the DW to a combat rogue last night after some target dummy tests that confirmed what I experienced the night before.  It seems to proc with every fight for him.

Help me understand the mechanics and why hunters say that this is a great trinket to get?  It just didn't work for me.  I had about 4 passive arpen on my other set, so with that and my NES, I would have thought that that trinket would really assist.