It was very interesting today, as my sister rode a Reining horse while being coached by Clinton Anderson. His comment was that reining horses, like dressage horses, had to be dictated to. They could not decide that they would do a flying change here when a pirouette was required.
Likewise, a reining horse couldn’t decide to do a sliding stop when a spin was required.
So, while event horses need to take direction, they certainly can’t be dictated too, cause all riders screw up. An event horse needs to be able to say “nope, you’re wrong so we’ll do it my way” or “nope, you’re wrong, so let’s try again”.
But, given the right training and approach, they can still do lovely dressage. Just not all of them (or us) really have that desire. And sometimes, you’d rather be on a horse that’s gonna take you clean and fast around cross country than one who’s gonna be great in dressage, but that makes you work for it on XC.
Not all horses can do all phases well. It’s often a choice as to which you prefer.
Me? I want to be pretty certain my guy’s jumping whatever’s in front of him, whether I get it right or not.