Cuban had a nice quote about making the core of the team younger. They have switched from guys like Shawn Marion and Jason Kidd who were in their mid-to-late 30s to guys like Rondo, Ellis and Tyson who are late 20s early 30s.
That they have changed the rest of the core around Dirk from very old players (NBA standards) to players who are in or near their prime years (29-32) for winning in the NBA with Rondo, Ellis and Tyson Chandler. That this gives them a stronger foundation to build around for next few years (presumably 3-5 seasons) and a better chance of keeping the team strong as Dirk continues to get older.