I promised it last week. This week, I deliver: How is arms doing in patch 4.1?
Pretty darn well. I raided as arms Tuesday night and did respectable DPS (I was third for the evening, spiking between 17k and 19k DPS, depending on the pull), although I still fell short of my fury DPS. (I even managed about 17k DPS in a ZA run that same night.) For a 10-man raid, it was certainly a valid showing. On a dummy, arms seems also to come in second, but a close second to fury for me, with averages of around 14 to 15k.
What does this all mean? Well, it means if you're more comfortable as fury (which I am), you'll probably want to stick to it. But if someone who does not fully feel at ease with arms and the rotation can still put out valid raid and heroics DPS numbers, then for those of you who prefer the arms playstyle, I can't see a reason you shouldn't be able to do better. This means to me that arms is definitely raid-viable in patch 4.1 as of right now.