Uh...the hardness of a common warstrider is sufficient to negate the majority of weapons held by First Age troops up to Ashigaru, or Second Age troops up to Elite. Nothing about the warstrider design penalizes the parry DV, which is pretty easy to pump to high levels. That's significantly more than "peasant billmen." After that is the psychological impact. And, of course, at the end of it all is that you're assuming a singleton warstrider without supporting troops or other warstriders in battle. Especially for a terrestrial game, that's simply not how it goes down.