Parity has been slow to come to Big 12 football, compared to other major conferences:
SEC: Four champions the last four years — LSU in 2011, Auburn in 2010, Alabama in 2009 and Florida in 2008. From 1998-02, the SEC had five in five — Tennessee, Alabama, Florida, LSU and Georgia. To find the SEC void of parity, you have to go back to 1993-96, when Florida won four straight.
Big Ten: Three champs in three years 2008-10 (Penn State, Ohio State, Wisconsin), but Wisconsin now has won two straight. From 1992-96, the Big Ten had five in five (Michigan, Wisconsin, Penn State, Northwestern, Ohio State). And from 1999-03, the Big Ten had six champs in five years — Wisconsin, Purdue, Illinois, Ohio State-Iowa (they tied, with both unbeaten but not playing), Michigan.
Pac-12: The Pac has been top-heavy in recent seasons — Southern Cal won six straight league titles, 2003-08, and now Oregon has won three in a row. But from 1994 through 2000, seven schools won the seven titles available — Oregon, USC, Arizona State, Washington State, UCLA, Stanford and Washington.
ACC: Three in the last three years — Clemson, Virginia Tech, Georgia Tech. But historically, the ACC has had little parity. Virginia Tech won four in its first seven years in the league (2004-10). Florida State entered the league in 1992 and won the first nine titles and 11 of the first 12.