Wiki page isn't bad...
College Football Playoff - Wikipedia
Over the past seven years, eleven P5 champions have been excluded from the playoff. Of those eleven not selected, nine had two or more losses. No two-loss teams have ever been included in the playoff. Over the past seven years, a total of nine one-loss P5 teams have been excluded from the playoffs, and that includes three teams from this shortened year (No. 5 Texas A&M (8ā1), No. 11 Indiana (6-1), and No. 17 USC (5-1)).
There is just no data that supports an expansion beyond going to, at most, six. I think it should stay the same.
RTR,
Tim