Aw, he's cute. I love winter fur. Makes them look so much younger I think!
The picture of his right side is deceiving because I don't think the ground is level which makes his hind end look a lot higher than his front. He is a bit play-footed in front(toes out), and his pasterns are on the longer side, which makes for a smoother ride. :) His neck is joined onto his shoulders a little low, but could be improved by strengthening his topline. Strengthen Your Horse's Back with Belly Lifts at the Tail
Belly lifts are great, as well as stretches you can do for him with some treats. Good to do before and after riding, or either or. Learn to ride your horse better with Horse & Rider Magazine
Stetching is good to teach him to relax certain muscles so he can use them in order to start building more muscle.
I love his expression. He looks kind and an all-around fantastic horse.