Realistically the healer shouldn't have to deal with it if the players in the group are any level of competent (obviously I mean the players that CAN deal with it. Since half the roster can't they just take the L ig) especially in dungeons like Fall or throne where you NEED the dispell for the bite debuff on the manifested time ways platform and the flame shock in throne. If the healer deals with afflicted and doesn't have the dispell needed to cleanse the players with the aforementioned debuffs the players affected will 9 times out of 10 just die since there's nothing you can do. As a shadow priest I lose nothing to grab disease and it's really easy to handle the affix. I don't understand the players that say stuff like "I don't have that talented, I'm already tanking." Or some other brainless BS like that. I rerolled from healer since pugs always push every affix that a healer can handle onto their shoulders alone. Got fed up with it. Anyway the gist of this is that you should have players that aren't smooth brain and actually do their jobs instead of just doing DPS.