Overall there is less investment in variety and focus on simple explaination of "corporate numbers". This means the business model is simpler as you sell/demonstrate volume savings or R&D savings to higher managment by duplicating stuff. Ultimately though this can change your market as we see here, you balance the selling of extra volume of standard items to the newbies, rather than selling the more specialist stuff to die hards...and create new die hards, when they realise what they bought singles them out to not only visiting the world, but a specific part.
Rather than have a variety of steady lines they currently focus on looking for "the big one", and swamp it everywhere. Where this line is "reasonable" you get reasonable sales returns on stuff overall. (reasonable in terms of acceptance by general populace, not my personal opinion!). Princesses and pirates are akin to this sort of thing, they sold, they swamped the world, people get bored of them, the sales slow, they get swapped out for the next big one, usually trying to convince people they need to buy "it" because it's the same as the recent movie release. Where you think you've got the next big thing and you get it wrong....you get stitch, who should have remained a steady seller in the relevant area.
They should have a shop in each park that full of general merchandise, world of disney should cover this as well, and then each attraction and resort should stock mostly unique stuff. WOD, could also cover parks and resorts as well to a degree. If they took this approach and plugged it on resort tv etc, then they hopefully allow all guests to seek out what they want. You could flag "exclusive to this attraction" (only available here!) as a selling point of the stuff that you're selling, which should help it sell. I think you'd get away with quietly not marking the stuff sold by attractions that's also in WOD shop as well :-)