Disney has been fairly slow to do big shake-ups to itineraries.
The best news - years out - comes from Castaway Club parties for Gold+ on the longer cruises.
That’s where Alaska and Bermuda were brought up. Last year, it was talk of South America. A few years from now, Magic or Dream could be sailing South (I doubt the newest ships).
Until Gatun Lake maintains water sufficient for non-essential vessels, I don’t see a good reason to pay for priority lock usage. Yes, other cruises still are doing transits (at least partial).
(Yes, I have said much of this before. Maybe in this thread, even.)
I'll say it again : people who travel DCL primarily want a Disney experience. That means flying into Orlando, visiting WDW for a few days, taking Disney transportation to PC, transiting through the Disney created PC terminal, traveling to Disney created islands, etc. The majority of DCL cruises are 3-5 days and I doubt that will change anytime soon -- for a family of four, most itineraries are priced over $1,000/night and that's about the budget of most folks.
Disney's asking for as much or more per night for summer cruises from PC & FLL than Europe; on most cruise lines, Europe is double. Disney's expenses are going to be lower serving Florida (procurement for a single ship bouncing around Europe is going to be a premium) so little doubt in my mind those cruises are more profitable. IMO Disney continues to serve Europe out of necessity in keeping affluent travelers happy.
IMO, South America is a fantasy. Those are poor countries -- you'd have to rely on people from the USA flying into South America to keep the prices up, and even then Florida would likely be more profitable. There's a good reason there's few cruises from South America .