Reward the reformers wherever possible, I say. JetBlue has a great product, and forces the Six high-fare Families to lower fares on routes where they compete.
As obviously as the new DL JFK-MSY flights are a competitive response to JEtBlue, there is some truth I think to the claims in Delta's press release about international flights. Two MD-80s a day might easily be mostly filled with international travelers hooking up with DL's big int'l schedule at JFK.
Keep an eye on capacity. Delta's new JFK-MSY schedule offers slightly fewer seats per day than JetBlue. IF DL suddenly doubles or triples capacity on the route, at the same or lower fares, then they're getting predatory.
Need a new airline paint scheme? Better call Saul! (Bass that is)