The ports WERE the reason I chose a
Disney cruise over the others sailing out of Galveston in the first couple weeks of January, the only time I can go. Disney is FAR more expensive than RCCL, Princess, and Carnival, and I think for the six-day itinerary in particular, there was nothing to make many people who sail out of Galveston try them - they were going to the same ports the other cruise lines visited, for far more money. KSF certainly helped attract families.
My 8-day January 4 was supposed to go to Key West and Costa Maya. Carnival goes to Key West, but we haven't sailed with them yet, so I had not been there. I was really looking forward to Costa Maya as our first cruise 5 years ago was supposed to stop there, but between the time we booked and the time we went, Hurricane Dean struck it, so we went to Cozumel instead. Unfortunately, this time around the seas were too rough to dock, so we missed it again.
Too bad Disney didn't do the 8-nights to Key West, WDW, and
Castaway Cay out of Galveston from the outset. That would not have appealed to me personally, but I think it would have brought in more of their bread-and-butter (families and big Disney fans).