Well they already went to Epcot since the Princess Dinner is there. They also have Snow White and other M&Gs that appeal to them. Not to mention Nemo. There are things that appeal to that crowd. My friend has a 5 year old that is into Princesses and she loved Epcot. It is her second favorite park next to MK. They spent 3 days in Epcot because of how much they love that park and that was before Frozen was added.
Not to mention that target group also LOVES the duffy bear thing in the countries.
I am not that familiar with Disneyworld. When I think of that princess age group I think of the new fantasy land? Did not know there was a princess dinner in Epcot. I would be an example of the typical first time visitor who doesn't do research into the parks. The kind of tourist who asks what monorail do I take to get to Harry Potter world.