Correct, the show and books don't have to kill the same people, however in this case, I believe they have to. Both Roose and Stannis are obstacles for the protagonists. Roose/Ramsey are obvious--they're in the way of the Starks retaking Winterfell. I don't see how they could be allowed to live after what they did.
Stannis is claiming to be the king of the seven kingdoms. Dany is in the way of that and possibly Jon due to his heritage. Jon also can't be King of the North since Stannis wouldn't allow that either. (He wanted to name Jon a Stark and Lord of Winterfell. He was against Rob's declaration of independence as well.) Mel also has Stannis as the prince who was promised, which the books are foreshadowing Jon, just like in the show. Stannis has to fall for Jon to become the prince who was promised and king of the North. Stannis has to fall for Jon and/or Dany to rule the seven kingdoms.
So I agree characters don't have to die if they died in the show (like Barristan, for example), however Stannis and the Boltons are too big of obstacles to the protagonists and plot and will need to go.
I was going to say almost the exact same thing. Stannis must die.