When we took the shuttle van back to the airport, I talked to a lady who got a very nice, free room upgrade. She said that when she checked in, they said "We have you in a garden/island view room, is that correct?" and she politely said "Yes, unless you can do better?" and they upgraded them to an ocean view on the top floor! It was pretty quiet at the beginning of that week, though, so that's probably what made the difference. With Disney, it doesn't hurt to ask very politely.