I think if you take a careful look at Bonny's photos of the pony she was referring to and the pony Muffntuff is referring to you will see a perfect example of the difference between a "hinge" and a "ewe".
A horse with a ewe neck has a downward curving, rather than upward arcing, spinal column in the neck. I don't see that in Muffntuff's examples although a bit in her stallion but it is being masked somewhat by his heavy neck and the muscling on top.
There is nothing wrong with a horse in pasture condition. All my horses that aren't showing are in pasture shape. They are healthy and fit but not ready to step into a show ring. Their conformation is every bit as good as it would be if they were brought into show shape as most of them have been at some point in their life.
I am, I guess what you would call, an equine person, having had and loved plenty of all types of equines throughout my life, and conformation has always been conformation to me. I look for the same things in all equines. There are certain conformational faults that enhance performance and depending on what you are asking of your equine some of these faults may be more acceptable than others. I don't necessarily look for the same things in a horse I am going to drive or show at halter or ride on a hunter course or take on an endurance ride. There are even differences between some of the horses I take driving into the breed show ring or out on a CDE course although that tends to be more personality-wise.