R/D Ebon Dust Screecher

Introduction
While the concept of Ebon Dust Aura on Dervishes and Rangers is nothing new, I just wanted to spin it around somewhat by making it have some degen.

R/D ebon dust screecher

Ranger/Dervish
Level: 20

Expertise: 10 (9+1)
Marksmanship: 13 (11+2) or 15 if you want to run 11+4
Wilderness Survival: 9 (8+1)
Earth Prayers: 8

- Ebon Dust Aura [Elite] (Earth Prayers)
- Apply Poison (Wilderness Survival)
- Screaming Shot (Marksmanship)
- Pin Down (Marksmanship)
- Called Shot (Ranger other)
- Vital Boon (Earth Prayers)
- Mystic Regeneration (Earth Prayers)
- Resurrection Signet ()

Sideboard:
- Distracting Shot (Expertise) instead of Pin Down for less melee hate but interruption
- Crossfire (Marksmanship) instead of Called shot, if speed of the arrow is not an issue
Thrown out:
- Arcing Shot (Marksmanship) because of its slow-ness

The Design/Execution
-Ebon Dust Aura was the backbone of this build. It is used to blind melee targets at range (obviously) as opposed to utilizing melee range of soft-target Dervishes.
- Vital Boon is used to cover Ebon Dust Aura.
-Apply Poison is used to cover and pressure melee targets, which tend to have higher armor than most. (4 degen)
-Screaming Shot packs in an extra 3 degen for 7 degen in total. It also doubles as a way to increase the bow's raw damage as + damage is armor ignoring.
-Called shot is for targets with blocking stances (Kournan bowmen, anyone?) it is also the fastest way to apply conditions from a far range.
-Mystic Regeneration is to compensate for the lack of Troll Unguent. Be aware that it is an enchantment as well so Shatter storm and Gaze of Contempt will make you a bow-based degen at best.

Thoughts:
Ebon Dust Aura is pretty potent, but the problem is you need attack skills with low cooldowns to make the most of it. Called shot is ideal for this.
On a Dervish at best you have Wounding Strike, which is elite. That means a ranger can hit more (non adjacent) targets with it.
Unlike a Dervish, at least you can get some mileage out of it if your enchantments get stripped. :P

As always, comments are appreciated as long as you make them constructive and reasoned.