The article says:
"The purpose of the full cheek is to give the horse something steady to balance against when ridden on direct contact...In essence, the full-cheeks give him something to lean against...Iíve found that trained horses that are switched to the full-cheek will often resent the extra pressure on the sides of their face and often will lean into itóleaning in the opposite direction that you are trying to turn. Besides that, the single-jointed snaffle (which most full-cheeks are) put excessive pressure on the horseís tongue as well as poking into his palate, making him very uncomfortable."
To be honest, that is NOT why we started using full-cheek snaffles, and it does not in any way describe how Trooper behaves after a few years using a full-cheek snaffle. All the horses I know who are using them are ridden with a slack rein, and none use the bit to pull against. The picture posted earlier is how Trooper is normally ridden, with plenty of slack.
There was a time when Trooper leaned against it, pushing his nose to the outside of the turn, but he did that in any bit (we have also used O-rings, D-rings & eggbutt snaffles, single and double jointed). But that was because of how he balanced himself in the turn, and he was wearing a full cheek when we trained him to balance himself better so that he no longer shoved his head to the outside of the turn for balance. It was a balance and flexibility issue, and probably partially an inexperienced rider balance issue - NOT a bit issue!
Of course, I don't see thousands of horses. My sample size might be 6-8 horses tops. And no one wants me to do videos to teach riding...