One indicator is to look at Advanced Dining Reservations for the first couple of weeks in December. There is virtually no availability in any park. For example, Dec 7, any park: lunch early or late: Tiffins, Tonys, Jungle Navigation, Rainforest; dinner: Tiffins 6:30, Tony's 3:10. The others were all taken at the 60-day mark. So, even discounting for staffing issues, I'm guessing that the parks will be pretty busy.