One of the most overlooked parts of horsemanship is the effect that nature, training and animal husbandry have on natural gaits.
“Because, since he has left the ranks he is now on his own, given a free head and neck, free of all constraints, moving under his own instinct; he has acquired the habit of covering steep terrain. This habit is necessary so that the horse is prevented from falling, which he himself fears. But domestication as sometimes hindered him from acquiring the skill needed to keep him from falling, and he has not been allowed to get used covering the kind of terrain that could bring about those falls.” L’Hotte.
If man can destroy natural gaits, one would have to guess that modern horsemanship as accomplished that goal.
I spent two year riding with out aids, just feeling natural gaits and balances in a variety of natural terrain. I came to the simple conclusion that I do not have the skills to improve natural gaits.
If there is not outdoor work in the process of training a horse, I consider him circus trained and unfit for working outdoors.