Never been on a DC before so I do not know what they sell, but I would love for them to sell Disney Cruise Line pajama's, especially for kids, I would love to be able to purchase it as an in room gift, nothing like sleeping in new PJ's at a magical place/ship.
That pillow, that is on the new ships... For a decent price!
I would love it if they had a silhouette shop like they have on Main St at Disneyland. The silhouette of my kids from a couple of years ago is still one of my very favorite Disney souvenirs ever.