I am 100% with you on the sock sensor issue. I think it should cover the entire foot. I am guessing that doing that though, the sensors that would end up on the ball of the foot, would either wear out very quickly or cause a lack of balance / cause players to slip since a fighters weight is almost exclusively on the balls of their feet for the duration of the fight.
Reading directly from the rules on the WTF website, The head is clearly defined as "2) Head: The area above the collar bone" which is pretty clear and leaves no room for interpretation. Front, back, side, top, face etc it's all the head. Where there is room for interpretation is where the rules say that it will be regarded as a point when any part of the foot "touches" the head. because a touch to me means, regardless of power etc if my toe, comes in slight contact with any part of your head, I deserve 3 points. But we all know that does not happen.
The body however is not so clearly defined in the rules. "1) Trunk: Attack by fist and foot techniques on the areas covered by the trunk protector are permitted. However, such attacks shall not be made on the part of the spine." and further defined as "Trunk: As depicted in the following illustration, the area covered by the trunk protector between the armpit and the pelvis is the legal attacking area. Thus, trunk protector should be worn according to the rule on the size of trunk protector for each weight category and the physique of each contestant."
That my friend leaves a huge hole open for interpretation and, in my opinion, is what allows LaJust to get away with hogus that do not wrap around the back.
This my friend is only one small problem how to interpet any and all of the rules, I know in international play the rules vary somewhat but we must adapt and learn all aspect of the sport to really be a top level competitor.