Horses' behavior strongly depends on their education, training and the driver. A good one with a good driver doesn't give in to fear. You even can make a helicopter fly next to it if it is well trained. If FSD gets the perfection and you don't need to enjoy your driving it would be dull. It's like having a personal driver. What makes driving a car or a good horse (or whatever) fun is the interaction with them, the handling of your own decisions and your accuracy to carry out a manoeuvre