If they're going to have 5 major conferences and a Group of 5 then it should have been an 8 team playoff from the start. Power 5 champions and best Group of 5 team get in, with 2 at larges.
1 Clemson vs 8 UCF
2 Oklahoma vs 7 USC
3 Georgia vs 6 Wisconsin
4 Alabama vs 5 Ohio State
But it would be pretty difficult to schedule with 2 extra games after the main bowl games. Can't play on the first weekend of January because that's NFL wild card playoffs. They would have to play the semifinals on Monday or Tuesday then the championship game on Tuesday or Wednesday.