The problem with the logic is that even if all 5 P5 conferences have a championship game, there are still going to be 5 P5 champions - so, it's still a beauty pageant.

AND, there will still be teams like '11 and '13 Alabama that don't play in the conference championship game, but are unquestionably still in the top 4/8 - with there only loss to the number 1 team in the country.

OR, there will be teams that lose in the conference championship game, but that still have an argument ahead of other P5 champions (see Big Ten champ Wisconsin in 2011, etc.)

BUT, there will still be the counter argument that Alabama didn't have to play top-10 Missouri or South Carolina, because the SEC doesn't have a round-robin schedule.