I have been grinding the area for at least 100hrs so far, I got 2 full kabua drops early on and am 73/100 embers (unlikely to get the full drop) and this isn't about my progress here, just the sense of reward for the effort.

The issue here is the event that pops up seems pointless. I have probably done the event about 40 times so far and never have I once got a drop (although drops have occurred due to the normal group spawning part way through the event).

In almost all other monster zones when there is an event, there is a boss that drops with a higher chance of a decent drop, like a Black Distortion Earring at Primal Giants for instance. As I understand the full pieces of the Kabua and Flame of Resonance can drop during these events, but never have I got a fragment or ember. It is now an event I just ignore and move to the next pack.

You certainly get a boost in a bit of exp/trash when doing an event, but i have found it better to just not waste the time and continue grinding the normal groups to get more pity pieces per hour. The event gets very boring after 20 or so times where there is no sense of reward at the chance of progression on the pities.

Yeah you are correct, actually our whole guild had a discussion on if it was actually bugged (The event where multiple darkseekers respawn at a time) because in the amount of time I was there, I didnt get ANYTHING from that event, and I have been there nearly 50 hours. 

The mobs from the spawn events do not drop any shards or pity (other than that worshipping one that starts it).  They definetely need to fix that.

I got 3 full artifact drops and about 150 artifact shards before I got my 100 flame pity.  So glad to be done with that crap.

The blazing ember events are the only saving grace.