Oklahoma is coming off a 12-2 campaign which ended with a fourth straight Big 12 Championship and a second consecutive defeat in the College Football Playoff.There are a number of reasons why the Sooners could be worse in 2019, but here are the top 3:Note: For a more optimistic viewpoint, read part one of this series: Why the Oklahoma Sooners could be better in 2019.No more HollywoodOklahoma won’t be lacking in receivers for 2019, but it might still miss the speedy Marquise Brown, who is headed for the NFL.