Hoi! Our stance isnt that wide lol You must mean like in zenkutsu dachi stance when moving forward for example oi/gyaku zuki etc in which stance is more the long wide low stance you're describing. But generally ours kumite stance is about shoulder width. Why? Because one needs to be able to lift our front leg up off the floor comfortably and quickly (as for say mae geri keage/kekomi, , yoko geri keage/kekomi, and so on) If our stances was too wide or too narrow than about shoulder width this would either be impossible or just very hard to execute. There - my 2 cents for this morning what I meant was compared to kyokushin, shotokan has the wider stance, and maybe because a wider stance means more power. and is good for such techniques as the gyaku tsuki.