He looks a decent sort. Nice head/neck/shoulder. Neck set a little low for my taste but I suppose good for HUS/western disciplines.
He IS very over at the knee, which would be my major worry, since he's young so it's unlikely to be from overwork and more of a conformational issue. Unless he has been SERIOUSLY overworked in his short life which is of course a worry in itself. His hindlegs are also weak, sickle-hocked and with upright pasterns, but not the worst ever ever.
I'm also not a huge fan of his behind, but that could be mostly lack of muscling.
EDIT: Just to say he does like SLIGHTLY over at the knee in thr 2yr old pic, but no where near as bad as now, so something has worsened it, but probably because he was born with the tendency to go that way.
Also, are you sure that's the same horse! How different is his colour - wow!