This is true but every DPS warrior should also have an Arms spec because there are many fights where Sweeping Strikes is going to be a huge game changer. A few I can pull off the top of my head are: Stone Guard, Amber Shaper Un'sok, Wind Lord, and possibly Garajal the Spiritbinder if your raid is having trouble with adds in the spirit realm. There's potentially more but that's just what I can pull off the top of my head.