My thoughts in terms of balance:
-Cavalry needs nerfed in some way. In fact, I'm inclined to believe that hitboxes for them are off, how can it be I aim at the riders head(I'm on horseback) and my lance hits his horses legs according to my damage report in the chat box? Would also explain why spears literally never seem to stop horses.
They seem to be off for everything, even for the cavalry player. I main cavalry in Warband, so I'm not completely incompetent, and yet in Bannerlord I can't intentionally knock someone down as cavalry almost ever. My horse just does that weird "Hey you, just move yourself back 20 cm so I can get past, thanks" thing, even to enemies. And yet at other times I don't try to knock people over and all, and as such my model misses their model by quite an amount, and the result is them getting knocked over completely. My guess is that the client horse and the server horse are in two completely different locations. This would happen occasionally in Warband, e.g when you horse bumped something, your horse would go slightly out of sync with the server for some reason, and the result was that if you tried to do a tight controlled maneuver through a small gap you would crash into one of the sides, because the horse on your screen and the horse in the server were in two slightly different places. I feel like this is what Bannerlord's horses are like 100% of the time, but it's also a mess for the people trying to attack the horse as well.
My perspective on a rework of the horses would be:
-Fix the horse server location, if that is indeed the issue right now
-Pierce damage should do more damage through horse armor, specifically horse stabs to the front of the horse by spears(this way it's not a buff against the slightly underpowered light horses)
-It should be easier/the hitbox should be larger for a spear stab-rearing attack on a horse's front
-The helplessness time period of the rider should be reduced (right now you're completely useless and can't do anything while the horse is in it's rearing animation, which is really annoying, and sometimes needlessly life-ending if the enemy team has a competent archer).
-The rearing animation should be longer when you crash into objects at higher speeds
-Turn rate of slow/stationary horses should be reduced
-Turn rate for horses at higher speeds should be increased a bit
-The hitbox for a horse to bump someone over should be bigger(or fixed, at least)
-The time it takes to get up from being knocked over should be reduced significantly, by as much as 50%
-Lance/Spear stabs from stationary horses should do a lot less damage (right now it feels like they do full damage with no speed bonus, anyone else feel this?).
-Reduce riding skill for non-cavalry classes, and perhaps completely restrict higher level horses
-Horse rider needs more protection from their shield, although this is an issue for everyone, not just cav.
-Thrusting animation still has that weird delay, which makes timing lace stabs harder, as well as timing anti-cav spear attacks harder as well, but this is an issue for everyone as well