Encounter design has unfortunately reinforced this, focusing tank damage into more and more bursty moments in an attempt to challenge tanks. Over the course of Warlords of Draenor, tanks have been mostly self-sufficient, providing the vast majority of their own survival, with only minor direct assistance required from healers.
These may appear to be “nerfs” at first glance, but are actually part of a widespread adjustment to improve overall tank (and tank healer) gameplay, that includes reducing the strength/frequency of defensive cooldowns, and adjusting creature tuning to compensate. In the latest Legion Alpha build, tanks and healers will notice significant changes to the tuning on many of their defensive abilities.
