we have all we need: the agil/fast horses of low hp and armor, the mid and heavy horses with higher hp ando/or armor and less man. why change all that?
our real problem is the cost/effectivness thingy. everyone uses the horse that will work best for him without beeing broke instantly.
thats why i´d suggest (it has been done before) not to change the horses atm, but the upkeep for them, or price. whatever.
NO plated charger dude will be more effective than a courser or arrabian rider. And especially no warhorse dude.
So, although im pissed by only thinking about it: redo the prices according to effectiveness.
sth like courser=mamluk, arrabian=charger, charger=destrier. while decreasing the prices for heavy horses and increasing those of "mediums"
ahrg, only thinking about it is killing me : D
but seriously, why kill deversity in this game, this way we would see more of every kind of horse, and thats what makes things interresting. not burfing everything to be way similar at the end.