Have you tried the patch major arty?
Well yes, I agree that its good and finally useful and will definitely give USF another option for breaking PAK walls.
The point is that the balance patch changes were made in the context of the current patch, and right now the Major's Arty is 100% useless (unless you count using up Munitions as a purpose). Even if the Major Arty buff goes live (it should) it still won't fill the Scott's role for the many reasons that should be obvious.