SoTC should be exempt from the list as it is the only horse where you do not (as a player) directly input its controls. It is essentially a moving, dynamic platform that a player use - a modification essential for a few aspects such as aiming, maneuvering as a launcher to facilitate specific boss fights.
Other horses in general are just their for the sheer purpose of traversing; another vehicle; a speed-up option for the player. Nothing more, nothing less.
Edit: I have not accounted to what MGSV or The Witcher 3's horses, but from what I've seen, they fulfill their general purpose.