As someone who runs a control/support spec for dungeons, it’s highly noticeable how little damage we do. It makes perfect sense to me that this would be the case, letting the player make a choice to trade off damage for utility.
The problem, I do have though is that mob groups and bosses in dungeons have such high amounts of health, I can’t help but feel worthless when control isn’t much use (nothing to interrupt, no conditions to cleanse). If I could reliably tank the mobs with some buffs to passive defenses I would be perfectly content. But with not wanting a trinity style dungeon experience, I think that a large decrease to mob health would help make sure specs like mine don’t feel worthless when they don’t fill a particular niche.