Thanks for the physics statemnt Mattressi, and no thanks for Toldfield for bringing up this RL argument wich... we call bs when trying to balance a GAME.
Who cares about the fact a bump would actually kill someone, who cares about the fact that a wounded guy with an arrow in his feet wouldn't be allowed to walk or run that fast, who cares horses jump higher than the best ones, this way evading some pikeman, who cares about the fact that a slash to the carotide can leave the ennemy alive, providing he has 30 str and 10 IF, who cares about realistic arguments !
In a balance term, horses are OP. And it's not just a question of price (look at the number of people asking for a polearm/bow/2h/1h at a price of 60,000 gold), but of gameplay and ownage. You were killed by a couched LoC on a courser from the front, with your plate armor and 30str, and a pike ? Too bad, cav just needs to press X while you have to get the best timing and move to actually be able to stop the horse without diing. You were killed by a 1hand sword slashed from the horseman even though you stopped his horse with your polearm ? Too bad, hit boxes from TW ftw. You were 1hit by a cav with whatever weapon coming from behind that you didn't heard. Too bad, you can't feel the earth shattering when horses are galoping, and you can't hear them well either anyway. You got bumpkilled even though you blocked down ? Yep, hitbox ftw, the cav with his lance can hit in front of his horse without hitting his horse. Horse bumped you and other teammates to death, and hasn't receive any damage from that ? Yep, that's sad.
So now, we have some footman asking for a SPECIAL horse, or at least an item that fits in the "horse" equipment, wich requires 5 athletics and wich gives "+2 athletics, +2 PS, +2 PD, +2 PT". Cost is the same as a destrier. Let's call them SOCKS. How about it ? The requirement and the bonus are pure random, of course. But what's the answer to this ? HARDCODED. Even by implementing a very tiny horse, as big as a ant, wich gives the impression you're walking, you'll still won't be able to use items "non usable on horse", nor would you actually care about your athletics anymore.
Humm... then how to balance this damn horse, since we can't give footmen another expensive item. If you lower the horse life, cav will whine. If you add dmg to horse when the horse bumps, the cav will whine. If you make the horse more expensive, the cav will whine. But hey... this is Mount & Blade, and i'm pretty sure cav were supposed to be OP. So i don't have any idea about how to balance this thing, even more since we're playing a mod using TW engine, so we can't just tell TW to add another slot in the equipment sheet, or whateveR.
Good luck finding it, cause at the moment, cav is OP.