Please review the following movement tweaks
https://github.com/bdew-wurm/movemod/releases

Allows server admins to tweak many things related to movement of players, mounts and vehicles
Speeds
Weight limits for players
Min/Max heights, depths and slopes
Wind impact for boats
Loading ranges
Required skills

I support this.
Unfortunately, carts are so slow that aggressive animals catch up.
Animal husbandry is also not good because horses with speed skills do not go faster.
I have ebony horses, they go at the same speed.