My guess is that people who are on the DDP would be going to table service restaurants. They wouldn't want to waste the TS credits. So if this is attributable to the DDP I think it's:
1) decline in the number of guests who are purchasing DDP because of the 2008 changes, or because they want to tour without being constrained by having to make it to table service dining reservations every day
2) decline in the number of guests at WDW in total, possibly due to national economic concerns
3) faster turnover in the restaurants due to elimination of the appetizer from the basic dining plan
At any rate I must confess that I'd be glad if the restaurants were no longer TOO busy. If they're that busy all the time, the food and service suffers.
1-As DVC members we always had Florida family drop in over the weekend of our stay.
2-We were always honest about that with the front desk.
3-When they told me I would have to buy DDP for the entire time for each guest and it was not transferable from guest to guest I hit the roof. (very quietly and politely thinking I could "move" them to my view).
4-When I got a very terse email about needing a DDP for each guest for the length of the reservation I sent several more emails registering my disgust.
5-In 2007, Florida family did not visit and we decided to not buy the DDP in 2008.
6-We did not like the $1. discount for what we lost.
7-I eat alot, my family eats alot.
In 07' We did not waste any of the food and the snacks were enjoyed as loaves of bread, chips for the room, and while we sat at the airport waiting in line to get on the SW flight.
When the product does not fit the consumers need the vendor will realize a change in spending habits.