It seems that in 2D, HW simulates very well the final results of inf v cav fights. In 3D it might looks a bit too static but I am sure that JMM can improve that in the future.
What seems a bit odd however is that, often, the cav units insist too much and stay for long in the fire range of the squares (and guns). It is frustrating when a cav corp or a unit is send only to "freeze" enemy movements, not to break the ennemy line. That happens even with the "diversion" order. Ultimatelly the cav units get captured or distroyed without having done so much (apparently, may be I am wrong). In many battles I have played, most of the cavalery was routed in the first hours, on both sides.
It could be nice in the future to have distincts "charge" and "harassment" orders for Cav Units/Corps/Brigades.
In the first case the cav units would keep insisting until the squares eventually breaks down. That order will have be employed cautiously by the player, only when he feel that the opponent infantry moral is about to drop down due to several factors. If the squares hold, then the cav will pay the price...
In the "harassment" order the Cav units would attack by waves, just to keep the inf in square formation and call for arty support. They will not stay for ages (as now) in the close fire range of the squares and will keep moving to be a "not so easy" target for arty: they will have a longuer life time but in compensation less chance to cause a drop in inf moral and will never break a square, unless the inf moral is altered by artillery or infantry attacks. That would fill a gap that still exist in Histwar : the combined inf+cav attacks. I am sure that this will come once but let's be patient we already have a lot and JMM has only two arms...