I agree with Heidi that the setting up of technical courses is under the responsibility of the ride manager, but also the riders and the officials.
Take Dubai for example, the means are there to make even in the desert a challenging trail. it is just a question of proper design of a course. Example : there are plenty of "green belts" in the area so why not drawing a technical single track inside this 'forest', like the one snaking in the so-called bad lands in Steph's course in Oreana (when you have to go around the sagebrush). This is a good way to force the riders to have a better equitation (the word has felt:-) ) and would also obviously slow down the horses.
What about climbing up this nice hill in Abu Dhabi overhanging the endurance village ?
What about dropping rocks on some parts of the trail ? What about keeping the deep sand portions in place of manicurng the trail...
It is just the effort to suggest that to the Sheiks. Why would they not like that ? They come to Compiègne, to the Tevis, to the Quilty, to Florac, to Belgium, etc... and if they keep coming that means that they like it !!!