We jump purely for cross training. She's an endurance horse. We do a ton of conditioning on trails, to the point of trails starting to become too much like work. It gets boring and doesn't work her brain. Occasional arena work mixes it up (for her and me!), is great cardio, and uses different muscle groups.
Her racking gait is suppose to be performed quickly, with energy and rapid footfalls; while trotting is suppose to be slower, steadier, and with a long, flowy stride. I COULD trot her if that would be better. She's trained to trot and gait.
You're probably right, on that she doesn't know she's suppose to canter slowly. Not sure what to do about that... I've been working on transitions, and that's slowed it down a bit.
We did gymnastics and trot poles to start out. I wouldn't mind going back to those for a while. This is only our second time doing courses, so going back to the basics wouldn't hurt my pride too much.