Well the resort pool is fun, and the kids' splash play area is very nice, but I can't imagine spending three days there with even the most water-enthusiastic child. There are tons of other things you can do around WDW without going to the parks though - travel to the other resorts to eat and look around (Riverside is only a short walk away and you can use the pools there too if you want; at Animal Kingdom Lodge you can see the Savannah; Boardwalk is fun for a stroll around, etc), take an evening carriage ride at POR, ferryboat from POFQ to Disney Springs, mini golf, rent a water craft at one of the Magic Kingdom area hotels, perhaps a water park if you want something bigger?
Andre