As others have stated...he looks like a very sweet boy!
A solid colored background would make it easier to see the outline of his body. I have a feeling that the white in front of his withers makes it appear that he has a bit of a ewe neck. I don't think this is necessarily true.
He's a bit steep through the shoulder which may make it more difficult for him to lengthen his stride. He's also lacking muscle in his back and loin. The lack of muscle makes it appear that his back is too long. I think that a good riding program might help that out. Starting him on some gentle hills might make a big difference in his overall appearance.
Either way, he's a nice looking horse and I'm sure an absolute joy!
He has a high wither point, I think that kills the look of the neck as well...but unless you are looking for a good jumper it only means difficulty placing the saddle...
I love his color, he has a nice head on him...I agree that a little more muscle on the hind end would make a huge difference over all
Let me just say this.
A horse with good conformation [that is very proportionate] you can measure from their ears to their withers [the length of their neck] and it should be exactly the same as their withers to the highest point of their rump [where the large rump bones are]
Meaning, by the looks of the pictures, his neck is kind of long for his body.
Other then that he is REALLLYYYYY cute. He has SUCHHH nice coloring!!!!