If Baron Davis doesn't have the worst contract in the NBA, he certainly is up there. The Los Angeles Clippers' guard has been a major disappointment since coming over to the team with a five-year, $65 million contract in 2008. He's been out of shape physically, and he's feuded with the team's head coaches.
Diop and Carroll are both players who don't produce for the Bobcats, with long-term contracts for a combined $10 million/season or so through 2013 (about $4 million less than Davis per season for the same time frame). However, Augustin is a relatively young, cheap replacement for Davis, and he could be a good fit since shooting guard Eric Gordon tends to act as the playmaker in half-court situations. Augustin's playmaking ability is poor, but he is a good shooter that could thrive playing more off the ball.
As for the Bobcats, CEO Michael Jordan is desperate to win after coach Larry Brown resigned. Davis still does have talent, and would probably improve the Bobcats on the court, despite his baggage.