The Priest hits less hard than most of the trash in SSC, let alone the bosses. That’s why DPS Warriors often hold her off to the side for many guilds. The actual Tanks on that fight are dealing with the Shaman, Hunter, and the boss himself.
Caperfin pushes this concept every time he hawks his stupid guide:
The claim that Shamans can “fully tank” all content is an outright lie, and he disregards one of many shortcomings as irrelevant for comparison. That’s claiming Shaman are competitive, and we both know they aren’t.
It is, but you’re not seeing that because it is likely due to a lack of significant DPS on your backside.