We went to WDW for the first time when DD was 5. We loved the zero entry pool, community hall, and playgrounds @ SSR. Now they have the Grandstand section with the horses that shoot water and the pool bar. SSR is nice to "come down" from the excitement of the parks, easy access to DTD, and the "wild life" -- bunnys, ducks, herons, etc., on the water.
My hunch (no data, staying with same DD, who is now 11) is that AKV will provide continuous stimuli that don't allow for the down time for the family...at your DD age. We're planning that DD will have her "quiet" time in the morning, when mom and dad want to sleep in, on the balcony watching the animals. And the eves, she can head to the community hall and have some "solo" time for herself without us hovering.