Yep.
Adds have to die fast or else your group gets overwhelmed and eventually wipe. A few of the bosses have to die within a certain time or else they’ll end up doing an unhealable amount of damage to the group. I don’t think we need to say anything else about the enrage timer.
So, if every group were to take the lowest performing specs including frost dk, bet he’d be taking back everything he said about frost being fine.