Actually no it was necessary sansa has been a very passive character little more than an object to be acted upon by others, by giving her adversity to overcome they've changed that giving her an inner strength she's severely lacked.
Now she has agency.
Now it's valid to dislike the r word as a plot device but it's far better that she becomes a fleshed out character than remain a pawn, plus it's not like she was the first person he did this to, theon suffered a far worse form of violation and broke because of it, then there were the girls he used and then hunted down for sport it's his modus operandi to abuse others for amusement.
