The question that remains unanswered for me is whether there are general rules about what is good for each horse when it comes to balancing weight. Could it be that the conformation of some horses allows them to carry more or less weight on their front or their haunches in a healthy manner. Is it really better for all horses to carry more weight on their haunches when ridden?
Haven't got time to read the rest but for this, yes, there is a simple answer. Some horses have more talent to carry humans in a correct way than others. That is what the old masters looked for in horses in the first place, second their ability to carry a bit and be able to bare spurs etc.
Third, a working attitude.
So it is never a questions of horses being able to take more weight in the front, it is a question of horses who automatically take more weight in the back.
That is why I do not understand why modern (sport horse) warm bloods are used for 'dressage'.
The breeds for dressage are those bred in 1400 and before, the old European old warmbloods like Andalusian, lusitano, kinsky, lipizzaner, kladrubber, knapstrupper, frederiksborger, friesean etc. They carry more weight in the back by nature and thus hardly need reins (if at all)
So the less a horse is able to carry weight with the hind quarters, the more you have to groundwork the horse to develop that before you ride him, and the more guidence he'll probably need in the saddle. This is what Klaus tries to explain.