I have played a few gens on horseback now. Its plenty fun.
What really annoys me when I make a heroic charge into a mass of players is the peasant with a pointy stick that puts my maxspeed jumping horse to a standstill instantly. And then unable to move because another peasant is standing next to my horse.
Consider changing the weapons that have rearing ability today to "Bonus against horse" , giving them double dmg or something.
The higher tier horses.. war horses should be able to push over a footman even at low speed.
Maybe not do any dmg, but push him over.. or atleast be able to push past him.