Horses usually look kinda gangly at about a year too. The legs grow fast, they get hip high, and its not often their most photogenic stage. I think your guy is looking good for a young bull. You might find that adding beet pulp or full tank helps drop that rear flank. At his age, he is burning up all his intake putting on frame and by acting like a little bull, so to get that little extra fill, you will need to feed him extra forage. I think a little tail head hair to set will also make a difference on the appearance of his hip. Just curious, but what is his current weight and hip height?