I don't have the standard in front of me, but:
he looks long, but I think it might be how far back his back feet go to make the hocks vertical with the ground. I think technically, you should be able to draw a vertical line down from the butt bone to the ground and the back toes touch that line with hocks parallel to the ground.
It looks like he is rocking back a little on his front feet - probably the way he's stacked and the long stretch of the back legs.
Overall he looks good to me.
disclaimer: I have no experience judging conformation - I love all Dobermans
