The Question was directly asked on Karl Holz On our 2014 Med cruise. His answer was " we are trying to find a way to do them".
We currently await the fall cruises of 2016 to come out at the end of this month, then it's winter to spring out later this year then summer 2017 out in March next year.
With the Magic basically going to Europe each year as its a moneymaker, and the Wonder going to Alaska another money maker then with four ships there options have been limited.
The two newer ships a Dream and Fantasy have been tied to Port Canaveral until 2017.
They have said from summer 2017 one of the ships ( most likely the Fantasy) may in the summer move for a short time.
Do it is on there radar, but there are other markets they sell for better in the summer than New York, the cruises they did, we're not sell outs, and therefore they will allocate ships to where they make the most money.
Non cruise income in Europe and Alaska for say port adventures brings in a considerable income stream as well as high average cruise fares. A run from NY to PC and CC with WDW included doesn't have a lot of non fare income.
Will they go back? Yes, when, wait and see.