Gemming: survival or threat?
This problem has troubled me for a long time. My belief is normally tanks should gem for stamina and/or avoidance, unless you are already outgeared for the contents you are tanking.
However, somehow all of my guild's geared warrior tanks like to gem for threat (hit & expertise). (My main is a hunter and my alt is a tankadin/healadin.) We are a medium level guild that cleared normal ToC 25 and 4/5 ToGC 10. Therefore, it's not the case that the tanks are overgeared for everything, especially we have the new ICC raid now. I talked to one of the tanks. He said maintaining high level of threat continuously is vital to the raid, and the small amount of avoidance from switching the gems is not worth it.
What do you think? Should I insist? Or is my concept about gemming wrong?