I'm new to this, but the most obvious example and the only thing I can see is how far off you are on the model's right leg. If you look at the gesture of the pose, you can see there are 2 curves that are not properly represented in your mannequin. The first is an s-curve connecting the pit of the neck, to the model's right leg. It goes from the neck to the sternum and crotch and continues down the leg to the foot. The second curve is a c-curve that connects the model's left armpit to the foot of the same leg. From this I suggest you work trying to better incorporate gesture into your mannequinization.