A program can be written to counteract small handmovements, the shaking could also be implemented as natural gun shaking.
I dont think its very likely that Nintendo will ever incorporate a neutral position button, due to it making things more complicated. Therefore the bounding box is most likely here to stay. But within the bounding box, the camera can move with your hand, and not by itself, if the reticule is fixed.
Im only mentioning this because I think it will make a better system.