I think that I have figured out why Captain Shaw does not want to refer to Seven as Commander Seven, but I could be wrong.
We all assumed that Shaw’s refusal to acknowledge Seven by her preferred name was the result of a bias against ex Borg because of Wolf 359. But in this weeks episode Shaw explained his escape from the USS Constance during the battle of Wolf 359. Shaw was randomly chosen for a place on the escape pod by someone pointing and numbering those to board, with Shaw being one of the lucky chosen ones. Of course, this leads to survivors guilt as displayed in this weeks episode quite explicitly as a result of a liberal dosage of painkillers.
I think that Captain Shaw was chosen to survive after being selected as number 10. Number 7 could have been one of his friends who did not make it. Shaw may not want to refer to Seven as 7 because of this personal connection to the cold use of numbers leading to his survival of the devastating battle against the cube? Shaw’s surviving crew became a lottery of numbers, which combined with Borg designations could actually be triggering to him. Seven could in return explain to Shaw why her name is important to her, I have mentioned my theories about this earlier but cannot find my original posts.
I assumed that Shaw was a bully to Seven, but in this situation we could understand his motives and perhaps a heart to heart with Seven could resolve things somewhat between the pair. Shaw may one day be proud to call his Commander ‘Captain Seven’, in honour of his fallen comrades and out of respect for Annika.