There's a place for unilateral shrug training since compensation patterns typically come from one side being weaker than the other. If you know you have a weaker side, simply add a specific shrug variation to that side to fix the issue.
A standing one-arm shrug with a kettlebell is very effective. Hold onto a bench to stabilize the upper body, making sure to stand wide enough to create a stable base. Keep the back extended and pull the shoulder blade back and down. Use an incline or flat bench to target different areas and to learn stabilization of the scaps in different angles.
Look around your gym. Most trainees lack the calf thickness to suspend a pair of double striped knee socks, let along balance out the size and symmetry of the lower leg. Now look in the mirror. Are you one of them?
We can always count on Christian to give us some great new movements that, in addition to spurring new muscle growth, will elicit bewildered stares from all the ACE certified trainers in the gym.