But seriously, I hate horses in games. The only one they were good in was RDR, and even that kinda ruined it by keeping you from making a connection with your horse, even though it added realism I guess. It's more hassle than it's worth in games like Inquisition, and in games where it's needed like Shadow it's just annoying. I guess Epona isn't terrible, but she isn't useful either. Maybe in the new game.
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.