The NCAA basketball tournament gives a mid-major the opportunity to win it's conference tourney, then six consectutive games against "BCS" type schools and a national championship. That has not happened in my lifetime, but their is access. The facts are that the pundits who beg for a playoff, must realize the BCS 12 team conferences actually give you a playoff with a champion that represents you in the BCS.
StatePackMan, I don't know how old you are, but if you are old enough to be in college, there are non-BCS schools who have won the NCAA basketball tournament in your lifetime - although maybe not in your memory. Georgetown in '84, Villanova in '85, Louisville in '86, UNLV in '90, & UConn in '99.
But I really have to take issue with your statement that 12 team conferences actually give you a play-off in the BCS. The key part of the word "play-off" is PLAY. You can't have a play-off when teams don't play to get to the finals. At the end of the season, 2 teams are simply SELECTED to play a championship game based on the opinions of pollsters or the calculations of computers. No one actually had to rise to the occasion on the field to get to the next level. This is better than pre-BCS days when a championship was simply awarded after the bowls. A true championship can't be awarded; it must be earned.