As the Chicago Symphony prepares to bid farewell to Daniel Barenboim after next season, a lot of questions about the future remain unanswered. The first unknown, of course, is the identity of Barenboim’s successor, and as usual, the CSO is keeping a tight lid on speculation. But almost as important is the orchestra’s overall model for future success: “with attendance flat at 82 percent and an accumulated deficit of $19.4 million gnawing on the bottom line, the CSO, with its 2005-06 season, will introduce two new series in an effort to make its concerts more inviting to a larger audience.”