At the conclusion of last year's college football season, two Division-I schools could say "We're #1!" That's because the championship is decided by taking polls, and the two major groups polled (sportswriters and coaches) came to different conclusions about the top rankings. Since both teams were undefeated, there's no objective way to say which was better. A coalition of bowl games was formed a few years ago in order to match the top two teams, but contractual commitments foiled the coalition's plans this year. The situation improves next year; however, there is still no guarantee that the coalition will be able to identify two (and only two) teams that are clearly superior to the others.
As indicated in a previous column, I believe winning is overemphasized in amateur sports. It would be nice if university teams could play just for the joy of competition. But obviously that's not currently the case; and as long as fans clamor for a national champion, it makes sense to decide it on the field rather than in opinion polls. All other collegiate sports use a playoff or tournament system (as does football at the lower divisions). Besides, the polls tend to encourage less sportsmanlike aspects of competition, such as running up the score on an outclassed opponent just to impress a few more voters.
The main objections to a playoff come from educators and from bowl game sponsors. Especially at the Division I level, it takes at least a week to prepare for each game. Teams already play an 11 or 12 game schedule, during which football players have little time for studying. Faculty members don't want that period extended by several more weeks for a playoff. Bowl game sponsors have a more prosaic objection: they anticipate that playoff games would detract from their product, leading to lower attendance and TV ratings.
Since there are already many proposals for how to run a college football playoff, I'll add my two cents. First, to meet the educators' objections, a playoff system should replace some of the scheduled games rather than adding to them. Second, the playoffs should make use of bowls where practical, and create the possibility of interesting matchups to support the others. Here's my idea of how this might work: