Another minor detail I've just noticed: The rings at the guard have an actual purpose. It was common to press the thumb of the upper hand on the hilt against the blade in order to gain additional control. By that the thumb reaches beyond the guard, thus it needs protection as offered by these rings.
In turn the other hand can use the hilt as a lever, i.e. it allows for easy swings of the blade and precise thrusts as well.
In short, perhaps there should be a wider spread between the hands, with the thumb of the upper hand stretched out across the guard. Would probably make for more realistic stances in general.