So I take it StK does Sapph with less than 160 frost resist? You guys all have The Hundred Club achievement?
Actually we do, and we've been doing it every week just to do it quicker, and because our guild is so unstable due to boredom, someone new that plays with us every week lacks the achievement.
The reason people are bitching about your spec is very simple data: in raiding, there's barely such thing as utility. There's 4 total roles if you want to be specific, and that is tanking, ranged dps, melee dps, and healing.
Rather than worry about stuff like CS, your rogues/prot warrs/shamans of any kind can be used (based on their skill and not talents) to prevent such things as Heals or Kelthuzad frostbolts. It is boring to raid to some extent because you spend the majority of it performing one of the above 4 roles. If you're NOT performing 1 of the above 4 roles, you are hurting your own guild progression.
Do what you like because it's $15 dollars a month. Everyone was making suggestions to MAXIMIZE your dps, which is (should be) your pure role in a raid as a mage outside of making foods and ports. No one is saying you can't put out dps with your spec, they're pointing out that there's MORE you can put out and what you should go with because that would be your role in the raid.