I have been thinking about the horse mechanic and come up with two ideas, I feel that when you whistle for your horse it should come right to your side so that you can fluently jump onto it and ride away, this would make for some really interesting crime scenes or help in fleeing situations.
Second I feel the horse shouldn’t follow the road unless you press something. For example I felt that if you hold Shift (B on xbox controller) that the horse should gallop along the path but if you use the mouse or keyboard it should ignore the path and do as you say. I love riding and would be more enjoyable if I could choose whether it autopilots or I ride it the way I want.