At the core of it all is the problem that stances which spread the legs very wide are unathletic, and therefore no blow which both seems believable and powerful can come from them. A frequently repeated phrase in sports, including combat sports, is that the feet are often placed "about shoulder width apart" when performing motions that require significant force. If you watch Olympic fencing, you'll see that they start with their feet about shoulder width apart in order to lunge far ahead and touch the opponent first, and once they have done so, they find themselves squatted down low to the ground, with their trailing leg nearly dragging on the ground behind them, in which case they are then open to counterattack if they haven't already won. For reasons unknown, XIV's artists have mistaken that compromised position for one which a person would intentionally start with.