Here are some changes the Horse Update Part 2 could have
Ability to remove horse saddle
Ability to change horse mane and size
Ability to make horse move when is not ride by the player
Ability to get the horse clothes for winter
New textures, colors and models for the customizations
Ability to own up to 3 horses for Horse Upgrade owners
Every horse has it's own personality
1 New free horse
UI changes