I am not a horse expert but humanly speaking they look sad when they put thier heads down, like a dog that has been beaten down. Again I know nothing about showing but when I take pictures of horses and look at pictures ( One of my hobbies is photography) of horses I want to see thier beauty, strength, and confidence. In my personal opinion it is not relatable...hmmm...what I mean is if I saw a picture ( something like a poster) of a horse with it's head hanging down with/without the rider I would feel sad for the horse. I wouldn't go "WOW, that's stunning!" I guess when I think of dressage I think of something like a Tennessee Walking horse with it's neck held up high and it's tail lifted struting around with pride and confidence. If I watch a video of a horse with it's head down and the rider tugging frequently it looks brutal (to me a horse novice and very empathetic person).
When I watch a show or see a horse I want to feel in awe of the movements or training, you know like "WOW, that's so cool!" Confidence is beauty, just like a little child that says "look mommy at what I can do!" Whether they fall on thier butt or not doesn't matter because when they stand up wearing a huge grin and you can see pride in thier eyes, then you smile too.
Again I am a novice and know nothing about dressage, just giving a perspective to the average untrained eye and my artistic eye says "not pleasing to this eye."