I've become very frustrated trying to get spirits and essences. I run the zones nightly. I've only ever gotten 3 essences (2 from the same mob), and at one time I was getting spirits at a decent rate (enough to get a full set of the gear), but now they have completely dried up. I don't think I've seen one since the patch that put the adornment merchant in. We've been getting plenty of obols - in fact, sometimes there are 2 obols in a chest.
Essenses... there definitely is an issue there. I have only gotten two of these ever. Greater spirits, I still think are fine. They are the peak of heroic gearing, so shouldn't be common as heck. Yet they still are common enough to get 5+ in a day if you really want to. MAYBE put in some daily quest to clear 3-4 heroic zones and get awarded a Greater Spirit upon completion for those that feel the RNG hates them... but I'd bet people would get minimum 1 greater just doing the zones to complete the quest anyways.
That's the problem.. This is how it used to happen.. One in every 3 or so zones would get you a spirit. We had one run of Faceless that dropped one off every named. It just seems since the patch they're not dropping AT ALL. (At least for our group) It's almost like it's bugging out.. usually the last named will give you at least an obol, and we've had a handfull of runs where all we get is one piece of legendary gear and nothing else (Like it should have dropped a spirit, but it's not there)
