There are 2 14 day itineraries in November and 2 15 day itineraries in December. It looks like they're only doing back to back itineraries next fall. I would think it's because of the economy. People seem to not be able to pay for a full 14 day, so they're offering 7 and 10 day itineraries and making them a back to back for those that can afford longer cruises.
From what I've heard, the Allure is a fantastic ship, but it would be doing the same thing as Princess. A 7 day eastern and then a 7 day western.
Princess had what they called the Grand Caribbean which was an actual 14 day itinerary. You did not return to the home port. I believe that is what they are offering this year.
I have done 3 10 day cruises on Princess and can attest that they were great itineraries. Of course, I love the extra days and love 14 day itineraries, but then again, even 21 days isn't long enough for me
Just wish I had more money.
Sorry I don't have anything better to report.