Horses havent been touched for years and that is a shame because we have a variety, but sadly all the past developers balanced the horses by price, like armours helmets etc, which is wrong.
A steppe horse has the same speed as the plated charger
Anyway, lets get to the chase.
First of all we need to diverse horses into different categories.
1. Light horses
Steppe
Black steppe
Palfrey
Desert horse
Courser
Arabian warhorse
Light eastern warhorse
The above horses should be the fastest & have the most maneuverability of all the other horses but on the other hand weak.
2. Medium range horses
Sumpter
Rouncey
Slav horse
Destrier
Eastern horse
Barded and Heraldic barded warhorse
The above horses shouldnt be as fast as the light ones (-3 speed & turn rate for example) but stronger and have more charge damage due to the fact that they are a bit heavier
3. Armoured horses
Armoured horses should be slow as fuck, depending from their armour, have slow turn rate but deal a fuck ton of damage and take a lot of hits to be put down, again depending from their armour.
I will give you an example
Plated Charger - original stats
hit points: 150
body armor: 52
difficulty: 6
speed: 38
maneuver: 33
charge: 38
39,385
Plated Charger - my example
hit points: 170
body armor: 60
difficulty: 6
speed: 35
maneuver: 30
charge: 45
80.000
What I want to succeed with this?
More variety of horses to the battlefield, not depending by the horse, but by the build you want to play.
Sure, the plated charger is slow as fuck, but a 1h shielder wont be afraid to do a headcharge instead of trying to backstab you (looks at royanss)
Light horses will be fast, ideal for lancing sure, but the lancer will be forced to pick his enemies because of the weak horse.
Also, all the horses should be more expensive, up the difficulty a tad, and buff the lances a tad.
I am more than willing to suggest some stats regarding horses.