There is one debuff that i always wondered why it was missing. the "negate positive effects" debuff. What it means is, it blocks and prevents buffs such as enrage, regen, and armor from working. The difference from "removing positive effects" is that, first, you can't remove permanent buffs, second, removed buffs can be re-triggered instantly, third, it sucks because it's too situational. Now you ask, "wouldn't it be too op?", no, because it won't remove the buff, just negate it's effect temporarily. There are many really strong debuffs and buffs out there, but there isn't many reliable ways to counter them, adding such debuff could prevent even overpowered passives from working and add counter-play.