Of course as Carnival adds ships they can service more ports. They are always looking for a new market. The Fantasy seems to be booking solidly since they brought it to Charleston, so that is a good indication they could use another ship/port in the area. So you never know. The Fantasy class ships are new enough that they won't be retiring them soon so as the Magic and the Breeze come into service it would free up ships they could service other smaller or newer ports with.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise
NCL Dream October 2006, RCCL Mariner OTS June 2007, Celebrity Silhouette 2013