#30 - Aug. 24, 2017, 11:59 p.m.
There are a few specializations (including Assassination and Outlaw) that had some buffs removed or reduced in the latest 7.3 release candidate. Those buffs were added to the PTR to help adjust for the additional 15 item levels your Artifact Weapon will gain from the Netherlight Crucible, as some specs currently get more of an overall effectiveness increase from item level than others.
Since the Netherlight Crucible won't be available immediately when 7.3 launches, these buffs have been removed temporarily from the latest release candidate build. They will be re-added via hotfix a couple weeks after release, once the Crucible can be unlocked.
In the future, we hope to find a better solution for the disparity in effectiveness that weapon ilevel has between specs, but that won't be in 7.3.