I have played some pvp on my dervish, but I am by no means any good
That said, I never found myself in need of a furious mod. Usually AoB and Onslaught give you extra adrenaline as it is, and if I run a different elite, I usually switch to lower adren cost skills. You will be sitting on a vamp scythe most of the time, switching out of it when needed to a sundering (blind, blurred vision) or a shield set (when kiting).
I only used 20% enchantments when I ran EDA or Onslaught. But you switch out of it after casting the enchantment you want to last longer. I usually take a +30hp mod, but in the current flux I would think +5 armor is more useful.
As you can see, what you need is dependant on your build and the situation you are in^^
I also would like to know what others think of the +30hp vs +5 armor in general (so outside the current flux). I know this depends on the situation as well, but which is generally most useful?