Quaking is not bad at all. If you are a caster, get weak aura. It will help you plan out your dps/heals so much more. Grievous though can go to hell. There is nothing fun about that. Unlike Necrotic, it doesn’t go away after combat ends and Pride doesn’t proc Necrotic. Grievous is so punishing, especially in PuGs where people are like “gogogogo”. Certain healers like Disc Priests and MW have a harder time keeping multiple people up. There is nothing enjoyable about this affix.
If people were about the damage they take, then it wouldn’t be so bad. But there are plenty of PuGs where they don’t eat food (even when we have a Mage!) after combat and expect the healer to burn their mana to keep them up through Grievous.