Firstly just want to say love the game ! 600hrs in and still enjoying it !
I do feel like the number of mobs needed to spawn the Pestilence boss needs tuning down a bit. While its great there is a mechanic to force the spawn, when low on resources searching high and low for mobs in an area isn’t that fun for me. Quite often I will just farm the majority of an area ..say about 25-30% of the bar left and hop on another realm to do the same. I then go back to the first realm once the monsters have respawned to finish the zone off.
Not all zones are like this, but the big zones feel like a bit of chore to complete without burning mats to force the boss.