I think that with all things, you have to remember there are still "kinks" that have to be worked out - what will be nice about being on the Fantasy vs. the Dream is that the Dream will have had over a year to work out some of those "kinks" and
DCL will use that experience to avoid some of the same issues on the Fantasy. They can't avoid any that are design issues since the ships are built, but they can figure out how to address traffic flow, congestion, etc.
We won't do inaugural or even overly early sailings of new itineraries because we want to give them time to work out the details that need adjusting.