He has the hocks only a gaited mother would love...LOL! Is he a registered TWH and/or SSH? He is very flashy - people will be jealous of you for sure!
Gaited horses are a little bit different to judge - they should still fit together nicely - all parts working together, and your guy looks good. His back is a bit long BUT that's ok on the gaited guys b/c it offsets their longer hocks (which are almost always seen as a horse camping under too much on gaited horses) - otherwise he would be hitting himself to the point he would be dangerous. TWH's do a decent running walk when their overstride (back hoof print oversteps the front) by a good 14 inches or so.
To me, he looks like his breed dictates. Lanky, good angles, slightly sloped hip, a bit of a roman nose and a long neck that will counterbalance his swing once his picks up speed. Even with 75 more lbs on him, he will still look like a lanky greyhound with miles and miles of legs. He is supposed to. I think he is lovely!
Do you have any movement shots of him? I would pay money for him if I was horse shopping!