As for what the judge looks at in terms of the horse and rider combination, the biggest thing in the horse is a willingness to go forward from the aids, come back from the aids and submission to the aids in general - I guess you can group all of these points under submission. Going forward does NOT mean running flat out at a million miles an hour. It must be controlled forward, aka if you say jump, the horse says how high?. The paces must be free, balanced and maintaining a constant rhythm.
The rider must be balanced, have soft, quiet hands, a steady leg and strong position, with their aids quiet and effective.