The 2008 team is the best team in the KenPom era. However, they did not rely on just one superstar to get them there. Indeed, only two players played in at least 70 percent of the team's minutes. That made it difficult to rank all these guys. Yes, team accomplishments were mostly used as a tiebreaker in the rankings, but bumping guys who played in 2008 down a peg or two would in essence penalize them for playing on one of the best teams ever just because they played with other great players.
In any event, Brandon Rush ranks 17th because of what he did as a freshman and sophomore as well as a junior, leading the team in scoring despite wanting to get his teammates involved. The younger brother of JaRon Rush, whom KU lost out on after an, uh, interesting recruitment, and Kareem Rush, who went to missouri, Rush decided to come to Kansas and was rewarded for it, becoming one of the best Jayhawks ever.
He was basically given the keys immediately, leading the 2006 team in minutes played while he shot 47 percent on twos and 47 percent on threes. He shot 43 percent from three as a sophomore and 42 percent as a junior, and when you're 6-6 and can get that shot off whenever, naturally there's going to be demand to shoot the ball. Bill Self famously had Brandon Rush either run or bike whenever he passed up a shot he should be taking in practice. But Rush always wanted to get his teammates involved: he's the only Self player 6-6 or taller with 200 assists in his career.
Rush also was one of the most versatile defenders in college basketball, able to guard Steph Curry and Chris Douglas-Roberts in the same NCAA Tournament. It was no accident he finished in the top 10 in defensive win shares twice.
Rush is also one of the few Jayhawks to rank in the top 25 in points, rebounds, and assists. That, plus his defense, makes him a cinch for a top 20 Jayhawk ever.