If ST announces a move to the NSun, I hope SJ and Concordia Moorhead move up too. That would preserve ToJo and give back the Condoria-Moorhead St rivalry.
The NSun would be at 18 teams, at that point. I think you could pretty easily break into divisions and play all 8 other teams in your division and then rotate through the other division 3 at a time.
East - Minot, Mary, Crookston, Moorhead St, Concordia Moorhead, Northern St, SW Minn, Sioux Falls, Wayne St
West - Bemidji St, Duluth, St Cloud St, St John's, Concordia St Paul, St Thomas, Mankato St, Winona St, Upper Iowa