This will be our first trip to WDW -- just two adults, DH and me. We decided to try the
DDP, and I think it will work out well for us.
We go to DL about once a year, and usually like to have one sit down meal each day.
~A typical lunch at Blue Bayou runs us about $60 (no appetizer, and maybe sharing a dessert). We've never eaten dinner there because we felt it was just too costly -- but my understanding is that the lunch menu is now about the same price as the dinner menu since the refurb.
~Our last meal at Ralph Brennan's Jazz Kitchen was over $100 (shared appetizer and dessert).
~Waits for Rainforest were ridiculous -- we couldn't get in walk up at dinner, and had to wait about 45 min for a walk up for breakfast.
~We tried to get into the sports bar (ESPN?) for dinner, and were told on a walk up at 7:00 (tired and hungry) that we
might get seated by 10:00 -- we gave up and bought counter service.
~We managed to get a same day ADR for Hook's Pointe, but it doesn't seem as busy or popular as the DTD restaurants.
So...DL doesn't have the DDP, but guests still have trouble getting in to the restaurants, and the prices are still high -- even if you don't order appetizers and desserts for everyone in your party.
I looked at our list of ADR's, and with beverage, tax, and tip I can see our bill easily being over $40/person. After adding in CS meals and snacks, we will definitely get our money's worth. And we aren't eating in the most expensive places, either. Do the math and figure out if it works for your eating habits and vacation habits

If you usually bring groceries for meals and snacks in your room, don't like to take the time for TS, or are really light eaters, it's probably not a good deal for you.
The 4-miles-walked-per-day estimate seems really low to me. Last time I wore a pedometer at DL, one day we walked 17 miles.

No wonder my feet always hurt by the second day! But I don't usually worry about gaining weight on a Disney vacation, even with all the extra treats and restaurant meals.