While I have nothing but good things to say about the various details of this picture, I'd sugest that you focus on improving your anatomy skills before working on so much detail.
I personally find that the legs are a tad too thin in contrast with the torso. The hip probably threw about your conception of the leg width in comparison to the body. Also, considering that the arm is slightly bent, I'd say that it reaches too far down. You may also want to take a look at the neck; while the armour hides this, it is a bit elongated. Try working on the shape of the hips a bit too, I find they are a too far down. Also, the size and shape of the head; you might want to enlarge the head a bit, which usually gives the subject a younger look, and perhaps thin out this jaw-bone that makes this person look rather like a macho-man. On a personal note, I'd sujest moving the eyes further down the face to give it a younger feel.
I must also say, while many people find their major problem in the hands, you seem to tackle them rather well. (^_^)d
Don't be intimidated by this comment, this is only constructive criticism though to help you become a better artist. In fact the thing about the neck and the arms is only a matter of opinion, you may well like long necks.
Do keep in mind that you are a very good artist and I very much like this sketch we have here, and I will be waiting to see some more.