1. Horses don't stand still when they are idle. Make their tails sweep around would be a good touch.
2. When mounted, the horses don't stand still either, they tend to walk about, change direction, and you have to kind of control the horse constantly to keep him in place.
3. The galloping or walking animation should be jerkier. If you are not experienced with horseback, when the horse is walking, he can shake your guts out of your throat. A little more bouncing to the walking animation would be good. Also, when galloping, it was too smooth in oblivion. The moment the horse's legs pushes him upward, it should be very jerky.
4. Horses should have softer bodies. When standing still and you try to make him turn, the horse's entire body actually bends toward the direction he's turning. In oblivion the horses are completely rigid.
Any comments?