Sure, it's basically impossible to defend the BCS in its current form. But a playoff would be a definite improvement for two constituencies: fans of the 6-8 schools that (with varying degrees of confidence/lunacy) count on being in the national championship picture every year and want clear title to their prize, and people who casually/passively watch college football on television the same way they do pro sports.
Who's left out? Pretty much everyone else.
Despite the increasingly inaccurately-named Bowl Week and its parade of 7-5 Sun Belt squads versus 6-6 MACsters watering down the product, bowls are one of college football's longest and proudest traditions -- and one of the most enjoyable for the fans who follow their schools to these games, the same fans who make annual donations and buy season tickets to fund the whole operation. Television guy neither knows nor cares about these people, except that his show seems oddly less compelling when they stop showing up for reasons he doesn't understand.
Each season, 20-30 teams who wouldn't qualify for any practical playoff scenario actually earn (rather than fall into) a chance to close a season out right with some modicum of attention paid, at a showcase bowl in a warm, compelling destination. (Or Jacksonville, the eternal exception.) But if you expect non-playoff bowls to draw any media attention at the same time as the titans play quote-unquote "meaningful games" for three or more weeks in a row, you're kidding yourself -- and that attention is the sine qua non of continued existence for these games.
Bowl games are college football's cultural distinctive, and by providing a reachable goal, the best of them support an entire tier of aspirational programs. If winning an undisputed championship is the only thing that matters, and you're certain you'll always be in that discussion, sure, go ahead and advocate a playoff. But understand what you're throwing away, and who it matters to most.