Fury PvP

I basically can only read PvP warrior info on the arms spec, but my understanding is that MS is 90% of the reason to go heavy arms in PvP. Can you go deep fury and get Furious Attacks to basically keep the same heal debuff on the target while out-DPSing arms?

Yes the main reason is MS, but arms got also Unrelenting Assault, and combined with MS can put an exceptional pressure on healers. Also you can keep up MS all the time, while in Fury no because it's rng, so less reliable, and a healer need just 1 sec to refull himself or his ally.
Arms also got Overpower which is the answer to dodgy enemies, a thing that Fury doesn't have.
And lastly, Fury War takes way more damage because of Berserker stance and Death Wish.

So in the end arms got more reliable and powerful healing reduction, more precision hitting, and better defense.