Honestly, CoF could have stayed BiS if they didn't make changes to BC and removed our Artifact (although with how strength will work, maybe not). Also don't forget that the gap in ilvl was far lower at the time compared to now. I don't really remember, but what was the gap in ilvl between TK and Sunwell? 40 maybe? Not to mention gear had a lot less stats.
Anyway, I'm getting more and more excited for Arms, although I feel like getting excited about Warriors at the beginning of an expansion is always a mistake.