This is close to my preference as well. The only thing I would change is the Power/Group of 5 garbage. First, any team in the top 4 is in the playoff. Then, any conference champion in the top 12 fills the remaining spots. If spots still remain, the rest are the highest ranked at-large options.

Since 2007, using the Massey Composite for each year to pick at-large teams, here are your playoffs (Massey Composite ranking in parentheses):

2007
(1) LSU - SEC vs (10) USC - Pac-10
(2) Ohio State - B10 vs (7) Kansas - at-large
(3) Oklahoma - B12 vs (6) WVU - Big East
(4) VT - ACC vs (5) Mizzou - at-large

2008
(1) Oklahoma - B12 vs (9) Boise St. - WAC
(2) UF - SEC vs (8) Utah - MWC
(3) Texas - Top 4 vs (6) Penn St. - B10
(4) USC - Pac-10 vs (5) Texas Tech - at-large

2009
(1) Alabama - SEC vs (9) Ohio St. - B10
(2) Texas - B12 vs (7) Boise St. - WAC
(3) UF - Top 4 vs (6) Oregon - P10
(4) TCU - MWC vs (5) Cincy - Big East

2010
(1) Oregon - P10 vs (9) Wisconsin - B10
(2) Auburn - SEC vs (7) Ohio St. - at-large
(3) TCU - MWC vs (6) Oklahoma - B12
(4) Stanford - Top 4 vs (5) Boise St. - WAC

2011
(1) LSU - SEC vs (8) Wisconsin - B10
(2) Alabama - Top 4 vs (7) Oklahoma - at-large
(3) Oklahoma St. - B12 vs (6) Boise St. - at-large
(4) Stanford - Top 4 vs (5) Oregon - P10

2012
(1) Notre Dame - Top 4 vs (8) Georgia - at-large
(2) Alabama - SEC vs (7) Texas A&M - at-large
(3) Oregon - Top 4 vs (Stanford) - Pac-12
(4) Florida - Top 4 vs (5) Kansas St. - B12

2013
(1) Florida St - ACC vs (8) Missouri - at-large
(2) Alabama - Top 4 vs (7) Michigan St. - B10
(3) Stanford - Pac-12 vs (6) Ohio St. - at-large
(4) Auburn - SEC vs (5) Baylor - B12

2014
(1) Alabama - SEC vs (8) Miss St. - at-large
(2) Oregon - Pac-12 vs (7) Ole Miss - at-large
(3) TCU - Top 4 vs (6) Baylor - B12
(4) Ohio St. - B10 vs (5) Florida St. - ACC

2015
(1) Alabama - SEC vs (8) Iowa - at-large
(2) Clemson - ACC vs (7) Notre Dame - at-large
(3) Oklahoma - B12 vs (6) Stanford - Pac-12
(4) Ohio St. - Top 4 vs (5) Michigan St. - B10

2016
(1) Alabama - SEC vs (10) Western Michigan - MAC
(2) Ohio St. - Top 4 vs (8) Oklahoma - B12
(3) Washington - P12 vs (6) Penn St. - B10
(4) Clemson - ACC vs (5) Michigan - at-large

In 10 years, this method would have left out only one conference champion in lieu of an at-large selection from that conference - in 2011 TCU won the MWC but finished 18th in the rankings, so Boise St. got an at-large bid as the #6 team in the country.

Italicized teams are teams that finished outside the composite top eight but received a bid based on their conference championship. Teams left out with higher rankings than the lowest seed would have been #8 UGA and #9 Florida in 2007, #7 Alabama in 2008, #8 Virginia Tech in 2009, #8 Arkansas in 2010, and #7 Wisconsin and #9 USC in 2016. Sign me up for that please.