With the addition of cavalry into the game, I think there should be a more dedicated anti-cavalry unit to cause them to not be able to blindly charge at people and run them down as easily. I realize that as they are new, horses will likely be altered in their stats, but I still believe it would be a nice addition, as it would not only provide more defense against horses, but also add 2 new classes to the game, both of which are also historically accurate as well. Mounted lancers could have long spears instead of a sword that would not only help them out-range other cavalry and infantry in melee, but these would function similar to lances in Mount and Blade, which are very slow to swing, and so if they miss, they'd likely be killed very soon after. As for infantrymen, Pikemen would be armed with an even longer (about 1.5-2x the flagpole length), more cumbersome spear that would essentially have an anti-horse bonus, as it would be able to damage cavalry (as well as infantry running at them, though not if the pikeman was running and the enemy was stationary) by simply being "readied", or holding down fire, similar to the Cheval de Frise. However, to make sure that this wouldn't allow for pure superiority between infantry, it would also have the same slow attack speed as the lancers' weapon, do damage comparable to the flag pole against infantry, and when doing the high damage attacks against targets running at them, and slow down movement speed by 15%.
Thank you for taking the time to read my proposition. I believe these units and weapons would cause players to plan their attacks instead of blindly bum-rushing on a horse and taking down multiple people by simply running into them.