Slower tempos - there are whole schools of dressage that believe that to get proper collection, the horse must be moving at a slower tempo so the joints have time to compress then rebound.
The passagey trots so oohed and ahhed over today used to be considered incorrect and I don't think they should be a goal for a WD horse..
I get what you're saying LongRide, but I'm positive you didn't remove the impulsion/energy from your horse prior to, or during, your work on collection. You wouldn't have made it to where you're at if you had. I'm not seeing impulsion or energy from the WD currently being ridden. And I don't think they can ever achieve collection by slowing the horse to a jog. It removes the energy, the impulsion, from the gait.
Impulsion as defined by the USDF: Thrust, releasing of the energy stored by engagement. The energy is transmitted through a back that is free from negative tension and is manifested in the horse’s elastic, whole-body movement
The biggest issue with dressage is that you need all the components of the pyramid in order to develop the horse correctly. You can't remove impulsion and ever get to collection... You want relaxation, suppleness, contact, straightness, and impulsion in the training level horse. Of course these will be at very low levels compared to a higher level horse, but the idea has to be there. Then each part is improved upon as you continue to train the dressage horse. The straightness gets better, the contact becomes more consistent, the suppleness increases, etc. Same with impulsion... you start with it at a level your horse can do, and build on it. Asking for a little more, and a little more, each time horse is physically capable of giving more. But you can't ever get collection without impulsion, contact, suppleness, straightness, rhythm.. they aren't independent of each other. You can't remove impulsion.
The basics form the correct foundation of the progressive training of the horse, independent of the execution of specific test movements. The basics include: pure rhythm with suitable tempo; relaxation/ suppleness/ elasticity/looseness; correct contact/connection; impulsion, straightness, and longitudinal balance suitable to the level and exercise–in other words, all criteria of the Pyramid of Training/Training Scale.
I don't see impulsion in the WD that is currently being ridden. And I don't see a way that those horse/rider combo's could ever achieve anything resembling collection as defined by USDF. At that point, they're just doing a pattern class on a well trained western horse. But it's not dressage. You can't leave part of the training scale out, and assume you'll get a dressage horse. That's why so many dressage riders can't make it past Second level. Yet, somehow, western dressage will achieve what a great many dressage riders cannot, all while ignoring a basic element in the training scale....? It's not possible.