I think Terminal A is a long way from being torn down and rebuilt. The new terminal which I think will be called Terminal 1, will be built to a certain size and then they built out as they grow. I believe all flights will move to this terminal.
My guess is terminal A will become a service UPS/Fed Ex terminal or torn down. Not sure how much cargo they do out of RDU when UPS/FED Ex and DHL are not included. I don't think it is a big lift airport like others, with so much of the international mfg gone and much of that was sent to Charleston/Norfolk and put on ships (Tobacco, furniture, etc) . Some is still left in eastern NC, but not much "time sensitive" stuff like PCs, tech equipment where the margins drive "JIT" logistic systems. Most of the stuff today will go by the big 3 (FedEx/UPS/DHL) for US shipments. My guess is the first phase of Terminal 1 will be in 2008/2009 and the will build on this terminal until 2020.
Depending on demand, will decide on how many gates they can fill. They could use more gates now, but the problem is we are running out of carriers. I would like to see Southwest to continue to grow to a mini-hub but they were eyeing down and still may be, Charlotte for that. (Now USAir is alive, maybe not). I would like to see Frontier Airlines come in as we need direct flights to Denver (RDU lost the UAL direct 50 seater). Another possibility is Jet Blue, but the NYC/RDU travel lane is full of competition now. We especially need direct flights to Denver, LAX, San Jose and San Fran.
As for the comment on international flights, I don't see RDU being a large international destination/point and question if we will ever get another large flight in the next 15 years. (does not include junkets to Freeport or San Juan) With the airlines consolidated, that become less and less of a chance. They are shoring up, cutting costs and driving everything they can to hubs they will keep. One of the likely choices of direct flight is Frankfurt, but the airlines have that so wrapped up out of their current hubs, it is doubtful.
We don't have the size needed for Asia as well as airlines sweep west to pick up people for those flights (LAX, ORD, Detroit, SFA, Seattle) with the few Asian east coast flights out of the big hubs Atlanta and JFK. I fly a lot and around the world and would love more direct international flights but we are lucky to have this ones we have like RDU-->LGW which is full of Eskers, IBMers, Body Shoppers and others. We would have to be a hub again........but I don't see that happening. But who knows what will happen in the next 15 years.