Far Cry 5, another highly anticipated game, came out in the end of March and it still is not added to SW. GoW came out just a couple of days ago.
They add it when they add it. You could ask SW about that, but I doubt you'll get a better response from them. But since the game is popular, it will appear in the programm sooner or later. It just might be sooner if enough people send them their saves, I guess.