one thing i react to is the lower part of the torso is in a difrent angle from the top, as if he is spun his hip counter clockwhise in relation to upper torso, maybe you ahve that intention but i would sugest to tone it down a little as it apears a little to much of a twist
The neck can also apear a little to thick in relation to his as its now bit of a what one se on a body builder, and rest of his shoulders and so dosent refer him to be that well build, i would sugeste make the line be a bit concave at the back and also font under his chin near the line suggest a adams apple to make him get a better neck and also look athletic build.

Ja, you are right on money with the torso twist. I did want to make it look as if he 'spun' slightly but after standing back and looking at it good, i see I fail bad xD
As for overall body, I always had unrest feeling that I make head too small contrast to body size and shoulders

you can make a easy relation as 3 heads should fit in the torso

Yes! I have heard of measurment methods like that! and others like 7 (give or take) heads stacked would determine proper hight proportions, ja?