In my experience, things don't go as well as some people like to think.
First, when your itinerary is switched from 3 sea days to 2, you will lose all of the onboard entertainment you have booked on the lost sea day. Second, in trying to accommodate you for those is next to impossible, because they are already booked with the lucky passengers whose sea day reservation didn't change.
Also, I never book ship excursions. So to scramble at the last minute and research new ports is near impossible with less than 24 hours notice till I depart my home. I like to avoid shore excursions in ports that are crowded and when ships change itineraries, there is no way to know how many ships will be in port since DCL may not be the only cruise line to alter their itinerary.
If you look at the ship excursions, you have no way to tell if the ones you want are booked or not, or if they are even offered. Now you will have to be on the ship as early as you can, spending time in line and may still not be happy with what is offered or available. What a great way to start a vacation!
I also book the itinerary I want. Regardless of the reason for changing course, I'm not really happy about it.
I'm so sorry this is happening to those sailing next week. You will have a good time, but it won't be the time you thought you were going to have when you booked on opening day.