Even if Katrina had never occurred, several changes could happen in the 8+ months between now and your flight time. Most airlines -- and I'm not just talking about Delta -- revise their schedules every 2 or 3 months. The flight times could change by a matter of minutes, or by a matter of hours; a non-stop could disappear and then two months later reappear.
Customer contact regarding flight changes varies from airline to airline, and I'm not sure what Delta's SOP is in that regard. I wouldn't be so quick to blast Delta for poor customer service on this.
Many frequent travellers and professionals post regularly on the Transportation Board. I'm going to move this thread over there, since it's more of a transportation issue than a Katrina issue.