I think Carl Hester's book that was published a couple of years ago gives a great "real life" description of "good" dressage conformation. He also describes which of his match up to it and where they are let down.
Sadly I think people do breed horses like this - (especially the Germans), narrow, no barrel, swan necked, no front & without the ability to move correctly in trot - hence the one leg on the floor pose!!
Give me correct confOrmation any day!
If that were the only horse that could score at dressage, then I couldn't have got two 8s and the rest 6s and 7s even a prelim on my old nag! She is exactly the opposite of that!