It just seems to me that it's a lot of time to spend to formalize a name change. If the issue is one of being called ministers, everyone at the table gets to be called minister because that helps, I guess, in terms of their status.
What's odd is that it seems to me that the implicit claim is that somehow sitting around the cabinet table, our Prime Minister would be less inclined to take their views and ideas seriously if they're called minister of state than if they're called minister. This is more a question for the minister, frankly. Did he decide to call them ministers to help him take them more seriously around the cabinet table?