An armoured horse and armour+shield for yourself pretty much makes you immune to range. It was like that before, and its even better now. The drawback for ranged immunity is a lot of money.
If you're cheap and use a rouncey or similar, well, you really have no right to complain about your horse dying.
Especially if you're charging an archer straight on who shoots your horse in the brain. Really. No shit it can get one shot.
@ cav fighting spears. You either need an armoured horse one that manoeuvres well. So either slowing down and tanking the hit with your horse or making the spearman miss.
Also, theres a sound mod out there for louder horsies.