This is a good move. If JI hopes to serve the business travelers in RDU, they need to serve major business centers served by the other big boys, like CLE, DTW, CVG, MEM, MSP, ORD or MDW, and so forth.
The last few cities JI has added have been on non-competitive routes to smaller markets (BUF, CMH, LOUISVILLE, IND), and while I don't have a problem with any of those choices, there's still plenty of major markets needs to ad to serve the business people of RDU.
Glad to see PIT, this may be a sign that JI wants to go against the big boys. Or, maybe it's a message being sent to US. Maybe JI isn't so happy that US does so much hub avoiding point to point service out of RDU, such as BOS, LGA, Stewart, DCA.