The thing is, ground work should very directly relate to mounted work. It should be a preperation.
For example; When working a horse in the round pen, most NH will try to disenagage the hind quarters by bending aroudn and putting pressure on it so that the horse swings aroudn like a gate, heavy on his fore legs and with the hind end going around like a whiplash. Would you want to ride a turn like that?
Ok for emergency one rein stop, but not what I want if I am preparing for a turn or roll back.
My trainer works such that when she is asking the horse to come to a stop or turn around and go the other direction that the horse look in, bend nose in, follow nose in , think "around" the turn with their head, prepare body by pausing and bringing weight BACK over the hind a bit, then reaching around with the front legs . Totally different. That is the kind of turn you want to ride, so that is the kind of turn you strive for in ground work.