Midas is a beautiful horse. At that, his back end looks fine to me. O_o Comparing it to the other horses on the page.. Looks the same to me. But would definitely be a great horse, if he is really that responsive and loving of his work! = ) As long as you feel like you can spend hours upon hours with him when you first meet him, it's all good.
His legs make me nervous. It looks like he has little/no heel and that is causing too much slope in his pasterns which can put a lot of strain on those tendons. He also looks camped out in the back and seems to have a very weak loin/croup connection. Guess it depends on what you would want to be doing with him but I don't think he would hold up well under a heavy work load.