Come to think of it. The rider's legs are not useful for bending the horse in the ribs, simply because this sort of bending has no part in the straight, upright horse. Exceptions of this rule have been discussed. This fact raises another question. Are the rider's legs useful to generate impulsion. Can and should they activate the horse's hind legs jointly or individually?
For me a new understanding of human/equine unity arrived with viewing this video of Alexander Nevzorov. The rider's legs not in conflict with the horse's torso. Their function not to demand but to accompany impulsion.
Craig Stevens speaks of never denting the horse. The distribution of dematomes in the rider's legs and for that matter body hints at the complete authority, which the rider makes known to the horse not by what he does but by his presence alone. The horse's nature is to move forward. Why double up on it?
The rider's legs can come in to help and support the hand. But do they have to? There are many ways to rule out complications and, in the end, the horse is most comfortable and at ease directed by the rider's hands, copying his body's posture and if needed propelled by a signal in his heels or held back by his leg's length. This sort of seat permits the rider's perfect balance and complete relaxation (more precisely Losgelassenheit). His motor impulses flow liberally and copiously to the horse, which, in human/equine work sharing fashion, puts them into motion. There are no conflicting signals. The horse reads and does the rider's will. Not surprisingly love is the supporting force.