I agree, there isn't much else that I would add. You already know that he is sickle hocked. His long back was the first fault I noticed, I do not think that his neck will get MUCH thicker, he simply looks to have a long thin neck and a large head that may never go together "great" but very sweet expression. Compliments to his long thick tail, I have a few horses here who would be jealous of that. From the photos and threw the fuzz I'd say his weight looks spot on! Keep working with building his muscling, if that is a goal to you.