These are not all that great confo shots, but I'll give you my best.
His neck is thick and tied in low, creating the illusion of a too-big head/neck. He is also butt-high. Maybe straight in the rear two, hard to tell from the pics. I'd also say he is weak in his pasterns.
Having said that, I don't think It's a big deal, he is a major-cutie and you all are cute together