Warlocks have a SIGNIFICANTLY easier time with the cursed thralls, only because their melee actually has quite a bit of reach (more than Titans and Hunters). It is possible to hit one on the very edge of your melee and only lose less than half shields, instead of all but a sliver of health. Doing this can blow up an entire pack of cursed thralls without getting you killed if you hit the lead one. Unfortunately, that also means that you only get rewarded for the one kill, and it does take a little bit of practice to get right. As for Urzok the Hated, he himself isn't too much of a problem. But the fact that he spawns during public events AND when enemies move against each other... He can be extremely hard to deal with, especially since he doesn't spawn right away. You will get a message above your super bar when he does. He hits exceptionally hard (saw him 1-shot an unsuspecting 29 preoccupied with other Hive). Also, a note: when killing Acolytes and Wizards with void damage, Wizards are worth 5 Sullen Hearts, while Acolytes are worth 1. It does not matter what difficulty the mission is, so you can run level 6 or 7 moon missions or level 30 hard mode missions and get the same rewards. I would recommend either farming the Refinery and Grotto in the Cosmodrome, or the Chamber of Night. Both have a decent number of low-level witches and acolytes.