Does movement only matter in dressage? Horses who prefer the trot doesn't mean they aren't athletic. There are a ton of different variables on why a horse hesitates the canter. This particular one, I just see he has not found the correct balance to be able to beautifully carry himself.
I see this horse's balance on his front end which disables his hind end from coming up and underneath himself. I think he's fairly well put together, and I don't see anything huge that would disable this horse from learning a correct balance to be able to do lower-level dressage movements.
No, he may not float like a 'dressage' horse can, but he can def. Learn to carry himself better.
Some horses are born with the ability to track up naturally, others can easily be taught. Just because this horse does not track up and use himself like he could, doesn't mean he lacks the ability all together. He can learn.
He looks like a nice all-round kind of guy that if his balance were to be helped he could do many different things.
In riding, a horse's energy is like a river- guided by the banks but not stopped by them.