I doubt it stays 12 personnel once everyone is healthy. McVay should have employed 12 personnel when the Rams were facing 6 man fronts. He never did and he has undying faith in his system. He blames every failure on poor execution.
I really hoped that the Super Bowl against the Patriots would have opened his mind to being more variable but it hasn’t seemed to.
Personally I’d welcome more 12 personnel, or a healthy mix anyway. It could give Puka and Kupp a rest and save them for the playoffs.