To me the first thing that stood out was his neck, it looks like an ewe neck, but I could be wrong. The way the girl rides him might be a part of why, considering the way she keeps his head up like that with a tight rein. Also, it looks like one of his feet, particularly the left front might be clubbed because as he goes around close it looks like he's going toe-heel instead of heel-toe. I'm probably wrong and just trying to find faults with this horse.
These are the only two pics they have of him on the site lol.
Thanks in advance!