She has no right to be frustrated about it, she ruined countless lives. That she can walk up to one of her victims, who happens to be her sister, and talk about it like all she did was spill some milk, is just wrong.
I don't need to see her weeping about it all the time, because it doesn't need to be brought up all the time, but when it does, I'd like her to react like someone that's aware they did something wrong.
The difference between Scott and Wanda is that Wanda is still ultimately responsible for what she did. Even if you subscribe to the idea that Doom messed with her once she got the power, it doesn't change the fact that Wanda sought him ought and asked for the power. Scott didn't. It was forced on him, and there was nothing he could do about it.
Chuck Xavier is about as great a hero as Magneto. Even from the start, the difference between them was paper thin.