you might be right,but im sure runes stack on the original skill ,
Ive also been testing ' RUSH OF ESSENCE" passive vs VQ on my bears build. Seams to me ,a better mana regen , and i doent have to stop bears ,only to drop skills. Since most of us use 3 spirit skills. this might work better for the wd's using the gru feast/grave injustice combo and having to use a mana return skill, so basicly it will give you a few more bears cycles , to finish the job!
so walk up to mob/ elite pop mass con/horrify start spamin bears for a few cycles pop spirit walk/ soul harvest/dmg rune , and continue to spam bears, with grave/grusume- your buff and cool downs/mama should be good for next pack.With ne mana regen on items , should replace the need for your off skills in fight
* if ne one tests this , lmk how it works for you
this might be a over looked passive for this new patch , with vq - spirit vessel ,or rush of essence /pierce the viel/vq might be a good combo