OK, this is being debated in the Bowl SoC thread, but the problem is wider than that.
College Football is terrible at crowning a champion. It always has been.
At least back in the bad old days of the MNC, it was PURELY a beauty pageant. At the conclusion of the season, a bunch of journalists would vote, and the team that came out on top was declared the National Champion. Nobody made any claims about things being settled on the field. Heck, they couldn't be settled on the field when most of the teams never played anyone of note outside their own conference.
Occasionally you'd get lucky and a bowl matchup would be the #1 vs #3 and #1 would win (while the #2 team lost elsewhere), and the idea of which team was truly deserving of the title Champion was clear. Other years, not so much. You'd have bowl matchups of undefeateds #1 vs #10, #2 vs #7, and #3 vs #4, and when all three went chalk those journalists had to decide which victory was most impressive and vote accordingly. [Or more accurately, just keep #1 at #1, because they won, and #2 and #3 were left out in the cold despite finishing the season undefeated.]
That's just stupid. It's based upon an outmoded notion that the Champion should be college football's "best" team, which is a subjective measure by any rationale mind.
Things got better with the BCS and CFP, because at least there's an effort now to match up the best teams with the best teams, but still.... That's subjective. Who are the best teams? Is it who the AP, Coaches Poll, and a couple computer models say are the best? Is it who the committee says are the best?
The NFL doesn't have this problem. The NFL selects playoff teams based *entirely* on what happens on the field. Win your division? You're in. Lose your division but have the best two record [with tiebreakers] of the remaining teams in your conference? You're in as a wild card. From there, once you're in, you're in. You can become the champion if you prove it on the field, even if you're not the "best" team--as we saw when the wild card New York Giants beat the 18-0 New England Patriots. No, the Giants were NOT that year's "best" team. But nobody can say they didn't deserve that trophy.
NCAA basketball [mostly] doesn't have this problem. Win your conference? You're in. Now, for the at-large selections, "fairness" is a different question, but every team in Div-I knows that if they win their conference, they're in the dance. At that point it's up to them to go win it. And whichever team that is, even if it's not the "best" team in the country, they're the one that deserves to be called champion.
See the difference?
Some people in CFB want to crown the "best" team the champion.
Others want the most deserving teams to have the opportunity to earn the championship on the field.
How do you "deserve" a shot? Win your conference. If you can't manage that, one can say that you don't "deserve" to be a champion over the team that won your conference. Even if your conference's 2nd-best team is better than every other conference champion in the country, they didn't "earn" their spot on the field. Any mulligans that allow you to get at-large berths should be seen as a bonus and not entitled. There are too many teams to have a mathematical "wild card" scenario like in the NFL, so to some extent the conference runners-up may still need to be a beauty pageant.
The only truly fair way to crown a CFB champion would be a 16-team playoff with all 10 conference champions and 6 at-large teams. That gives every team in the nation an objective measure by which they can get a seat at the table and a chance to play for it all. And it gives the rest of the teams in the country hope that with a good enough season, they *might* get the chance even without winning their conference.
A more realistic, but not perfectly fair, scenario would be an 8-team playoff where the P5 champions are auto-bid, and the other three spots are at-large but with preference given to an undefeated G5 conference champion over a P5 runner-up.
In either scenario, 2017 Alabama--who very well might be the "best" team in the country despite their record--would have undoubtedly been included as an at-large. But as a non-winner of their own conference, there is no way that they would have taken a slot from a team that deserved to be there for actually accomplishing something on the field--winning their own conference.