USDF and FEI are completely in the wrong on this one and it came out when a few years ago they looked at gaited horses. To me it comes down to elitism, those who do "Dressage" (and yes it is splitting hairs and comes across really badly and down right snobby) frown upon those who do not use big Warmblood horses. ANY horse benefits from dressage training and every rider should have basic dressage training to ride with suppleness, softness, and proper engagement.
There are reams of material showing what proper gaits are, what they look like, and how they should be performed, so for the USDF and FEI to say there is no consensus on gait is just flat our wrong.
We NEED more riders wanting to do dressage, even if they just stay at training or lower levels. Those who want to go on and do more intricate moves than bless them, but that doesn't mean that those who stay in lower levels, or on "non Warmbloods" should be excluded either. To me this speaks more on the terrible attitudes at USDF and FEI than anything else.
We should encourage people to go into dressage to learn proper riding and training of horses. Showing at dressage is just that, you showing how much training and communication you have with your horse and should never be used to divide people.