The first thing I've noticed as well is he's underweight, wormy, and seriously needs his feet trimmed. I would not be riding him at this point, I can't imagine how painful that is with those feet. You're just asking him to overreach and clip his front pasterns with those long toes. Though like Elana said, he is probably short strided. How long have you had him?
Very steep shoulder, flat croup, straight through his stifle and a weak coupling. He's a bit light on bone in his front legs but they aren't too bad.