Okay...
Basic guard is radically altered in WTF competion due to the fact that hand techniques are no longer much of a factor and hand techniques to the head are not a factor at all.
With no hand strikes to the head allowed, the guard has become a low, hands down position with the competitor leaning back. This both facilitates the execution of high kicks and the avoidance of one's opponent's kicks.
This creates a fighting style where the head is left essentially unguarded and leg techniques are essentially the only choice. This can be done because leg techniques are inherently slower than hand techniques and originate several feet below the head.
I consider the removal of hand techniques and the accompanying change that result to be a pretty large technical difference, particularly in an art whose poomsae contain a greater number of hand techniques than they do leg and foot techniques.
Daniel
Hand techs to the head are still not allowed but hand techs to the body are scored much more frequently than in the past. That is why we are training in Shotokan. The EBP's have changed Sport TKD radically over the last 2 years. More emphasis on punching and head kicking. We have changed are hand position to a much higher guard. Some of the old arguments just don't hold in regards to hand position in Sport TKD!