痛苦无常 meaning in English

unstable affliction

Unstable affliction : the silence from this ability is now subject to diminishing returns
痛苦无常：此技能的沉默效果现在受到“收益递减”的影响。
Why is it that affliction warlocks were deemed " useless without their dots " and given an ability that made dispelling useless against them , yet , this thought never occured to the priest developers when working with shadow priests
为什么痛苦术士被评价为“离开dot就一无是处”因此就给了他们1个让驱散失效的能力（痛苦无常），而这样的设计思路却没有应用到牧师的技能设计上来呢？