There will be no satisfying conclusion for you this update around, OP, they just tried and failed to make a compelling reason to use tower shields (more knockback). There was also no reason to use tower shields before the update. In a more sophisticated action RPG the solution would be to make larger attacks unparryable but make parrying smaller attacks even deadlier (Dark Souls) or to give you more passive protection when the shield isn't lifted (Mount & Blade). If they bother to address this again I can't really see their solution being anything but numerically nerfing parry bonus to the point where bucklers of the same biome of their respective tower shields can't quite reach the same block armor.