I actually quite like him despite how awkward he looks right now. He has a great hip and a large hind end, a decent shoulder, and great bone (especially for being only 3). I don't see his neck as an issue. If that video is a representation of how he is normally ridden, that is why his neck looks upside down, with lack of top line muscle. It is thin, but a young horse with a thin next can grow up to have an average size neck that's properly conditioned. It's a little low, which isn't ideal for dressage, but not so low that I think it will hinder him much (like you said, you're looking at lower level stuff, no piaffes for him!), and won't be a problem at all cross country. He has an excellent gallop, and actually a very nice, large trot, especially considering his rider isn't helping him, he's just sitting up there and steering. So far I like him. But I would really like to see him free jumped, over even just some small stuff first before deciding. He doesn't have to be a flashy hunter, but he has to be careful and safe.